Transmitting method, transmitting device, receiving method and receiving device

ABSTRACT

A transmitting device includes a plurality of transmission antennas, and includes: a signal processor which generates a first baseband signal by modulating data of a first stream, and a second baseband signal by modulating data of a second stream; and a transmitter which generates, from the first baseband signal, first transmission signals having different directivities, generates, from the second baseband signal, second transmission signals having different directivities, and transmits the first transmission signals and the second transmission signals at a same time.

TECHNICAL FIELD

The present disclosure relates to a transmitting method, a transmittingdevice, a receiving method, and a receiving device.

BACKGROUND ART

A conventional example of a communication method performed using aplurality of antennas is a communication method called multiple-inputmultiple-output (MIMO). In multi-antenna communication typified by MIMO,data reception quality and/or a data communication rate (per unit time)can be enhanced by modulating transmission data of a plurality ofstreams and simultaneously transmitting modulated signals from differentantennas using the same frequency (common frequency).

Furthermore, in such multi-antenna communication, an antenna having aquasi-omni pattern which allows a transmitting device to have asubstantially constant antenna gain in various directions in a space maybe used when multicast/broadcast communication is performed. Forexample, Patent Literature (PTL) 1 discloses that a transmitting devicetransmits a modulated signal using an antenna having a quasi-omnipattern.

CITATION LIST Patent Literature

PTL 1: WO2011/055536

SUMMARY OF THE INVENTION Technical Problems

There is a demand for further improvement in performance achievedaccording to a communication method performed using a plurality ofantennas.

Solutions to Problems

A transmitting device according to an aspect of the present disclosureis a transmitting device which includes a plurality of transmissionantennas, the transmitting device including: a signal processor whichgenerates a first baseband signal by modulating data of a first stream,and a second baseband signal by modulating data of a second stream; anda transmitter which generates, from the first baseband signal, aplurality of first transmission signals having different directivities,generates, from the second baseband signal, a plurality of secondtransmission signals having different directivities, and transmits theplurality of first transmission signals and the plurality of secondtransmission signals at a same time.

Advantageous Effects of Invention

According to the present disclosure, performance achieved according to acommunication method performed using a plurality of antennas can beimproved.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a diagram illustrating an example of a configuration of a basestation.

FIG. 2 is a diagram illustrating an example of a configuration of anantenna unit of the base station.

FIG. 3 is a diagram illustrating an example of a configuration of thebase station.

FIG. 4 is a diagram illustrating an example of a configuration of aterminal.

FIG. 5 is a diagram illustrating an example of a configuration of anantenna unit of a terminal.

FIG. 6 is a diagram illustrating an example of a configuration of aterminal.

FIG. 7 is a diagram illustrating an example of a state of communicationbetween the base station and terminals.

FIG. 8 is a diagram illustrating a relation of a plurality of streams.

FIG. 9 is a diagram illustrating an example of a frame configuration.

FIG. 10 is a diagram illustrating an example of a frame configuration.

FIG. 11 is a diagram illustrating an example of a symbol configuration.

FIG. 12 is a diagram illustrating an example of a state of communicationbetween the base station and terminals.

FIG. 13 is a diagram illustrating a relation of a plurality of modulatedsignals.

FIG. 14 is a diagram illustrating an example of a frame configuration.

FIG. 15 is a diagram illustrating an example of a frame configuration.

FIG. 16 is a diagram illustrating an example of a symbol configuration.

FIG. 17 is a diagram illustrating an example of a state of communicationbetween the base station and terminals.

FIG. 18 is a diagram illustrating an example of a state of communicationbetween the base station and terminals.

FIG. 19 is a diagram illustrating an example of a state of communicationbetween the base station and terminals.

FIG. 20 is a diagram illustrating an example of a state of communicationbetween the base station and terminals.

FIG. 21 is a diagram illustrating a relation of a plurality of modulatedsignals.

FIG. 22 is a diagram illustrating an example of a state of communicationbetween the base station and a terminal.

FIG. 23 is a diagram illustrating a procedure of performingcommunication between the base station and a terminal.

FIG. 24 is a diagram illustrating examples of symbols which the basestation and a terminal transmit.

FIG. 25 is a diagram illustrating examples of symbols which the basestation transmits.

FIG. 26 is a diagram illustrating an example of a state of communicationbetween the base station and terminals.

FIG. 27 is a diagram illustrating examples of symbols which the basestation transmits.

FIG. 28 is a diagram illustrating a procedure of performingcommunication between the base station and a terminal.

FIG. 29 is a diagram illustrating an example of a state of communicationbetween the base station and terminals.

FIG. 30 is a diagram illustrating a procedure of performingcommunication between the base station and a terminal.

FIG. 31 is a diagram illustrating examples of symbols which the basestation transmits.

FIG. 32 is a diagram illustrating examples of symbols which the basestation transmits.

FIG. 33 is a diagram illustrating a procedure of performingcommunication between the base station and a terminal.

FIG. 34 is a diagram illustrating a procedure of performingcommunication between the base station and a terminal.

FIG. 35 is a diagram illustrating examples of symbols which the basestation transmits.

FIG. 36 is a diagram illustrating a procedure of performingcommunication between the base station and a terminal.

DESCRIPTION OF EXEMPLARY EMBODIMENTS Embodiment 1

FIG. 1 illustrates an example of a configuration of a base station (oran access point, for instance) in the present embodiment.

101-1 denotes #1 information, 101-2 denotes #2 information, . . . , and101-M denotes #M information. 101-i denotes #i information, where i isan integer of 1 or greater and M or smaller. Note that M is an integergreater than or equal to 2. Note that not all the information items from#1 information to #M information are necessarily present.

Signal processor 102 receives inputs of #1 information 101-1, #2information (101-2), . . . , #M information 101-M, and control signal159. Signal processor 102 performs signal processing based oninformation included in control signal 159 such as “information on amethod of error correction coding (a coding rate, a code length (blocklength))”, “information on a modulation method”, “information onprecoding”, “a transmitting method (multiplexing method)”, “whether toperform transmission for multicasting or transmission for unicasting(transmission for multicasting and transmission for unicasting may becarried out simultaneously), “the number of transmission streams whenmulticasting is performed”, and “a transmitting method performed whentransmitting a modulated signal for multicasting (this point will belater described in detail)”, and outputs signal 103-1 obtained as aresult of the signal processing, signal 103-2 obtained as a result ofthe signal processing, . . . , and signal 103-M obtained as a result ofthe signal processing, that is, signal 103-i obtained as a result of thesignal processing. Note that not all the signals from signal #1 obtainedas a result of the signal processing to signal #M obtained as a resultof the signal processing are necessarily present.

At this time, signal processor 102 performs error correction coding on#i information 101-i, and thereafter maps resultant informationaccording to a modulation method which has been set, thus obtaining abaseband signal.

Signal processor 102 collects baseband signals corresponding toinformation items, and precodes the baseband signals. For example,orthogonal frequency division multiplexing (OFDM) may be applied.

Radio unit 104-1 receives inputs of signal 103-1 obtained as a result ofthe signal processing and control signal 159. Radio unit 104-1 performsprocessing such as band limiting, frequency conversion, andamplification, based on control signal 159, and outputs transmissionsignal 105-1. Then, transmission signal 105-1 is output as a radio wavefrom antenna unit 106-1.

Similarly, radio unit 104-2 receives inputs of signal 103-2 obtained asa result of the signal processing and control signal 159. Radio unit104-2 performs processing such as band limiting, frequency conversion,and amplification, based on control signal 159, and outputs transmissionsignal 105-2. Then, transmission signal 105-2 is output as a radio wavefrom antenna unit 106-2. A description of radio unit 104-3 to radio unit104-M−1 is omitted.

Radio unit 104-M receives inputs of signal 103-M obtained as a result ofthe signal processing and control signal 159. Radio unit 104-M performsprocessing such as band limiting, frequency conversion, andamplification, based on control signal 159, and outputs transmissionsignal 105-M. Then, transmission signal 105-M is output as a radio wavefrom antenna unit 106-M.

Note that the radio units may not perform the above processing when asignal obtained as a result of the signal processing is not present.

Radio unit group 153 receives inputs of received signal group 152received by receiving antenna group 151. Radio unit group 153 performsprocessing such as frequency conversion and outputs baseband signalgroup 154.

Signal processor 155 receives an input of baseband signal group 154, andperforms demodulation and error correction decoding, and thus alsoperforms processing such as time synchronization, frequencysynchronization, and channel estimation. At this time, signal processor155 receives modulated signals transmitted by one or more terminals andperforms processing, and thus obtains data transmitted by the one ormore terminals and control information transmitted by the one or moreterminals. Accordingly, signal processor 155 outputs data group 156corresponding to the one or more terminals, and control informationgroup 157 corresponding to the one or more terminals.

Setting unit 158 receives inputs of control information group 157 andsetting signal 160. Setting unit 158 determines, based on controlinformation group 157, “a method of error correction coding (a codingrate, a code length (block length))”, “a modulation method”, “aprecoding method”, “a transmitting method”, “antenna settings”, “whetherto perform transmission for multicasting or transmission for unicasting(transmission for multicasting and transmission for unicasting may becarried out simultaneously), “the number of transmission streams whenmulticasting is performed”, and “a transmitting method performed whentransmitting a modulated signal for multicasting, for instance, andoutputs control signal 159 that includes such information itemsdetermined.

Antenna units 106-1, 106-2, . . . , and 106-M each receive an input ofcontrol signal 159. The operation at this time is to be described withreference to FIG. 2.

FIG. 2 illustrates an example of a configuration of antenna units 106-1,106-2, . . . , and 106-M. Each antenna unit includes a plurality ofantennas, as illustrated in FIG. 2. Note that FIG. 2 illustrates fourantennas, yet each antenna unit may include at least two antennas. Notethat the number of antennas is not limited to 4.

FIG. 2 illustrates a configuration of antenna unit 106-i, where i is aninteger of 1 or greater and M or smaller.

Splitter 202 receives an input of transmission signal 201 (correspondingto transmission signal 105-i in FIG. 1). Splitter 202 splitstransmission signal 201, and outputs signals 203-1, 203-2, 203-3, and203-4.

Multiplier 204-1 receives inputs of signal 203-1 and control signal 200(corresponding to control signal 159 in FIG. 1). Multiplier 204-1multiplies signal 203-1 by coefficient W1, based on information on amultiplication coefficient included in control signal 200, and outputssignal 205-1 obtained as a result of the multiplication. Note thatcoefficient W1 can be defined by a complex number. Accordingly, W1 canalso be a real number. Thus, if signal 203-1 is v1(t), signal 205-1obtained as a result of the multiplication can be expressed by W1×v1(t)(t denotes time). Then, signal 205-1 obtained as a result of themultiplication is output as a radio wave from antenna 206-1.

Similarly, multiplier 204-2 receives inputs of signal 203-2 and controlsignal 200. Multiplier 204-2 multiplies signal 203-2 by coefficient W2,based on information on a multiplication coefficient included in controlsignal 200, and outputs signal 205-2 obtained as a result of themultiplication. Note that coefficient W2 can be defined by a complexnumber. Accordingly, W2 can also be a real number. Thus, if signal 203-2is v2(t), signal 205-2 obtained as a result of the multiplication can beexpressed by W2×v2(t) (t denotes time). Then, signal 205-2 obtained as aresult of the multiplication is output as a radio wave from antenna206-2.

Multiplier 204-3 receives inputs of signal 203-3 and control signal 200.Multiplier 204-3 multiplies signal 203-3 by coefficient W3, based oninformation on a multiplication coefficient included in control signal200, and outputs signal 205-3 obtained as a result of themultiplication. Note that coefficient W3 can be defined by a complexnumber. Accordingly, W3 can also be a real number. Thus, if signal 203-3is expressed by v3(t), signal 205-3 obtained as a result of themultiplication can be expressed by W3×v3(t) (t denotes time). Then,signal 205-3 obtained as a result of the multiplication is output as aradio wave from antenna 206-3.

Multiplier 204-4 receives inputs of signal 203-4 and control signal 200.Multiplier 204-2 multiplies signal 203-4 by coefficient W4, based oninformation on a multiplication coefficient included in control signal200, and outputs signal 205-4 obtained as a result of themultiplication. Note that coefficient W4 can be defined by a complexnumber. Accordingly, W4 can also be a real number. Thus, if signal 203-4is v4(t), signal 205-4 obtained as a result of the multiplication can beexpressed by W4×v4(t) (t denotes time). Then, signal 205-4 obtained as aresult of the multiplication is output as a radio wave from antenna206-4.

Note that the absolute value of W1, the absolute value of W2, theabsolute value of W3, and the absolute value of W4 may be equal to oneanother.

FIG. 3 illustrates a configuration of the base station different fromthe configuration of the base station in FIG. 1 in the presentembodiment. In FIG. 3, the same reference numerals are assigned toelements which operate in the same manner as those in FIG. 1, and adescription thereof is omitted below.

Weighting synthesizer 301 receives inputs of modulated signal 105-1,modulated signal 105-2, . . . , modulated signal 105-M, and controlsignal 159. Then, weighting synthesizer 301 weighting synthesizesmodulated signal 105-1, modulated signal 105-2, . . . , and modulatedsignal 105-M, based on information on weighting synthesis included incontrol signal 159, and outputs signals 302-1, 302-2, . . . , and 302-Kobtained as a result of the weighting synthesis. K is an integer of 1 orgreater. Signal 302-1 obtained as a result of the weighting synthesis isoutput as a radio wave from antenna 303-1, signal 302-2 obtained as aresult of the weighting synthesis is output as a radio wave from antenna303-2, . . . , and signal 302-K obtained as a result of the weightingsynthesis is output as a radio wave from antenna 303-K.

Signal y_(i)(t) 302-i (i is an integer of 1 or greater and K or smaller)obtained as a result of the weighting synthesis is expressed as follows(t denotes time).

[Math  1] $\begin{matrix}\begin{matrix}{{y_{i}(t)} = {{A_{i\; 1} \times {x_{1}(t)}} + {A_{i\; 2} \times {x_{2}(t)}} + \cdots + {A_{iM} \times {x_{M}(t)}}}} \\{= {\sum\limits_{j = 1}^{M}\; {A_{ij} \times {x_{j}(t)}}}}\end{matrix} & {{Expression}\mspace{14mu} (1)}\end{matrix}$

Note that in Expression (1), A_(ij) is a value which can be defined by acomplex number. Accordingly, A_(ij) can also be a real number, andx_(j)(t) is modulated signal 105-j, where j is an integer of 1 orgreater and M or smaller.

FIG. 4 illustrates an example of a configuration of a terminal. Antennaunits 401-1, 401-2, . . . , and 401-N each receive an input of controlsignal 410, where N is an integer of 1 or greater.

Radio unit 403-1 receives inputs of received signal 402-1 received byantenna unit 401-1 and control signal 410. Based on control signal 410,radio unit 403-1 performs processing such as frequency conversion onreceived signal 402-1, and outputs baseband signal 404-1.

Similarly, radio unit 403-2 receives inputs of received signal 402-2received by antenna unit 401-2 and control signal 410. Based on controlsignal 410, radio unit 403-2 performs processing such as frequencyconversion on received signal 402-2, and outputs baseband signal 404-2.Note that a description of radio units 403-3 to 403-N−1 is omitted.

Radio unit 403-N receives inputs of received signal 402-N received byantenna unit 401-N and control signal 410. Based on control signal 410,radio unit 403-N performs processing such as frequency conversion onreceived signal 402-N, and outputs baseband signal 404-N.

Note that not all of radio units 403-1, 403-2, . . . , and 403-N mayoperate. Accordingly, not all of baseband signals 404-1, 404-2, . . . ,and 404-N are necessarily present.

Signal processor 405 receives inputs of baseband signals 404-1, 404-2, .. . , 404-N, and control signal 410. Based on control signal 410, signalprocessor 405 performs demodulation and error correction decodingprocessing, and outputs data 406, control information 407 fortransmission, and control information 408. Specifically, signalprocessor 405 also performs processing such as time synchronization,frequency synchronization, and channel estimation.

Setting unit 409 receives an input of control information 408. Settingunit 409 performs setting with regard to a receiving method, and outputscontrol signal 410.

Signal processor 452 receives inputs of information 451 and controlinformation 407 for transmission. Signal processor 452 performsprocessing such as error correction coding and mapping according to amodulation method which has been set, and outputs baseband signal group453.

Radio unit group 454 receives an input of baseband signal group 453.Radio unit group 454 performs processing such as band limiting,frequency conversion, and amplification, and outputs transmission signalgroup 455. Transmission signal group 455 is output as a radio wave fromtransmitting antenna group 456.

FIG. 5 illustrates an example of a configuration of antenna units 401-1,401-2, . . . , and 401-N. Each antenna unit includes a plurality ofantennas, as illustrated in FIG. 5. Note that FIG. 5 illustrates fourantennas, yet each antenna unit may include at least two antennas. Notethat the number of antennas included in each antenna unit is not limitedto 4.

FIG. 5 illustrates a configuration of antenna unit 401-i, where i is aninteger of 1 or greater and N or smaller.

Multiplier 503-1 receives inputs of received signal 502-1 received byantenna 501-1 and control signal 500 (corresponding to control signal410 in FIG. 4). Multiplier 503-1 multiplies received signal 502-1 bycoefficient D1, based on information on a multiplication coefficientincluded in control signal 500, and outputs signal 504-1 obtained as aresult of the multiplication. Note that coefficient D1 can be defined bya complex number. Accordingly, D1 can also be a real number. Thus, ifreceived signal 502-1 is expressed by e1(t), signal 504-1 obtained as aresult of the multiplication can be expressed by D1×e1(t) (t denotestime).

Similarly, multiplier 503-2 receives inputs of received signal 502-2received by antenna 501-2 and control signal 500. Based on informationon a multiplication coefficient included in control signal 500,multiplier 503-2 multiplies received signal 502-2 by coefficient D2, andoutputs signal 504-2 obtained as a result of the multiplication. Notethat coefficient D2 can be defined by a complex number. Accordingly, D2can also be a real number. Thus, if received signal 502-2 is expressedby e2(t), signal 504-2 obtained as a result of the multiplication can beexpressed by D2×e2(t) (t denotes time).

Multiplier 503-3 receives inputs of received signal 502-3 received byantenna 501-3 and control signal 500. Based on information on amultiplication coefficient included in control signal 500, multiplier503-3 multiplies received signal 502-3 by coefficient D3, and outputssignal 504-3 obtained as a result of the multiplication. Note thatcoefficient D3 can be defined by a complex number. Accordingly, D3 canalso be a real number. Thus, if received signal 502-3 is expressed bye3(t), signal 504-3 obtained as a result of the multiplication can beexpressed by D3×e3(t) (t denotes time).

Multiplier 503-4 receives inputs of received signal 502-4 received byantenna 501-4 and control signal 500. Based on information on amultiplication coefficient included in control signal 500, multiplier503-4 multiplies received signal 502-4 by coefficient D4, and outputssignal 504-4 obtained as a result of the multiplication. Note thatcoefficient D4 can be defined by a complex number. Accordingly, D4 canalso be a real number. Thus, if received signal 502-4 is expressed by e4(t), signal 504-4 obtained as a result of the multiplication can beexpressed by D4×e4(t) (t denotes time).

Synthesizer 505 receives inputs of signals 504-1, 504-2, 504-3, and504-4 obtained as a result of the multiplication. Synthesizer 505 addssignals 504-1, 504-2, 504-3, and 504-4 obtained as a result of themultiplication, and outputs synthesized signal 506 (corresponding toreceived signal 402-i in FIG. 4). Thus, synthesized signal 506 isexpressed by D1×e1(t)+D2×e2(t)+D3×e3(t)+D4×e4(t).

FIG. 6 illustrates a configuration of a terminal different from theconfiguration of the terminal in FIG. 4 in the present embodiment.Elements which operate in the same manner as those in FIG. 4 areassigned the same reference numerals in FIG. 6, and a descriptionthereof is omitted below.

Multiplier 603-1 receives inputs of received signal 602-1 received byantenna 601-1 and control signal 410. Based on information on amultiplication coefficient included in control signal 410, multiplier603-1 multiplies received signal 602-1 by coefficient G1, and outputssignal 604-1 obtained as a result of the multiplication. Note thatcoefficient G1 can be defined by a complex number. Accordingly, G1 canalso be a real number. Thus, if received signal 602-1 is expressed byc1(t), signal 604-1 obtained as a result of the multiplication can beexpressed by G1×c1(t) (t denotes time).

Similarly, multiplier 603-2 receives inputs of received signal 602-2received by antenna 601-2 and control signal 410. Based on informationon a multiplication coefficient included in control signal 410,multiplier 603-2 multiplies received signal 602-2 by coefficient G2, andoutputs signal 604-2 obtained as a result of the multiplication. Notethat coefficient G2 can be defined by a complex number. Accordingly, G2can also be a real number. Thus, if received signal 602-2 is expressedby c2(t), signal 604-2 obtained as a result of the multiplication can beexpressed by G2×c2(t) (t denotes time). A description of multiplier603-3 to multiplier 603-L−1 is omitted.

Multiplier 603-L receives inputs of received signal 602-L received byantenna 601-L and control signal 410. Based on information on amultiplication coefficient included in control signal 410, multiplier603-L multiplies received signal 602-L by coefficient GL, and outputssignal 604-L obtained as a result of the multiplication. Note thatcoefficient GL can be defined by a complex number. Accordingly, GL canalso be a real number. Thus, if received signal 602-L is expressed bycL(t), signal 604-L obtained as a result of the multiplication can beexpressed by GL×cL(t) (t denotes time).

Accordingly, multiplier 603-i receives inputs of received signal 602-ireceived by antenna 601-i and control signal 410. Based on informationon a multiplication coefficient included in control signal 410,multiplier 603-i multiplies received signal 602-i by coefficient G1, andoutputs signal 604-i obtained as a result of the multiplication. Notethat coefficient Gi can be defined by a complex number. Accordingly, Gican also be a real number. Thus, if received signal 602-i is expressedby ci (t), signal 604-i obtained as a result of the multiplication canbe expressed by Gi×ci(t) (t denotes time). Note that i is an integer of1 or greater and L or smaller, and L is an integer of 2 or greater.

Processor 605 receives inputs of signals 604-1, 604-2, . . . , and 604-Lobtained as a result of the multiplication and control signal 410. Basedon control signal 410, processor 605 performs signal processing, andoutputs signals 606-1, 606-2, . . . , and 606-N obtained as a result ofthe signal processing, where N is an integer of 2 or greater. At thistime, signal 604-i obtained as a result of the multiplication isexpressed by p_(i)(t), where i is an integer of 1 or greater and L orsmaller.

Then, signal 606-j (r_(j)(t)) as a result of the processing is expressedas follows (j is an integer of 1 or greater and N or smaller).

[Math  2] $\begin{matrix}\begin{matrix}{{r_{j}(t)} = {{B_{j\; 1} \times {p_{1}(t)}} + {B_{j\; 2} \times {p_{2}(t)}} + \cdots + {B_{jL} \times {p_{L}(t)}}}} \\{= {\sum\limits_{i = 1}^{L}\; {B_{ji} \times {p_{i}(t)}}}}\end{matrix} & {{Expression}\mspace{14mu} (2)}\end{matrix}$

Note that in Expression (2), B_(ji) is a value which can be defined by acomplex number. Accordingly, B_(ji) can also be a real number.

FIG. 7 illustrates an example of a state of communication between thebase station and terminals. Note that the base station may be referredto as an access point or a broadcast station, for instance.

Base station 700 includes a plurality of antennas, and transmits aplurality of transmission signals from antenna 701 for transmission. Atthis time, base station 700 has a configuration as illustrated in FIG. 1or 3, for example, and performs transmission beamforming (directivitycontrol) by signal processor 102 (and/or weighting synthesizer 301)performing precoding (weighting synthesis).

FIG. 7 illustrates transmission beam 702-1 for transmitting data ofstream 1, transmission beam 702-2 for transmitting data of stream 1, andtransmission beam 702-3 for transmitting data of stream 1.

FIG. 7 illustrates transmission beam 703-1 for transmitting data ofstream 2, transmission beam 703-2 for transmitting data of stream 2, andtransmission beam 703-3 for transmitting data of stream 2.

Note that in FIG. 7, the number of transmission beams for transmittingdata of stream 1 is 3 and the number of transmission beams fortransmitting data of stream 2 is 3, yet the present disclosure is notlimited to such numbers. The number of transmission beams fortransmitting data of stream 1 may be at least two, and the number oftransmission beams for transmitting data of stream 2 may be at leasttwo.

FIG. 7 includes terminals 704-1, 704-2, 704-3, 704-4, and 704-5, and theterminals have the configuration same as the configuration of theterminals illustrated in FIGS. 4 and 5, for example.

For example, terminal 704-1 performs directivity control for receiving,via “signal processor 405” and/or “antennas 401-1 to 401-N” and/or“multipliers 603-1 to 603-L and processor 605”, and forms receivingdirectivity 705-1 and receiving directivity 706-1. Receiving directivity705-1 allows terminal 704-1 to receive and demodulate transmission beam702-1 for transmitting data of stream 1, and receiving directivity 706-1allows terminal 704-1 to receive and demodulate transmission beam 703-1for transmitting data of stream 2.

Similarly, terminal 704-2 performs directivity control for receiving,via “signal processor 405” and/or “antennas 401-1 to 401-N” and/or“multipliers 603-1 to 603-L and processor 605”, and forms receivingdirectivity 705-2 and receiving directivity 706-2. Receiving directivity705-2 allows terminal 704-2 to receive and demodulate transmission beam702-1 for transmitting data of stream 1, and receiving directivity 706-2allows terminal 704-2 to receive and demodulate transmission beam 703-1for transmitting data of stream 2.

Terminal 704-3 performs directivity control for receiving, via “signalprocessor 405” and/or “antennas 401-1 to 401-N” and/or “multipliers603-1 to 603-L and processor 605”, and forms receiving directivity 705-3and receiving directivity 706-3.

Receiving directivity 705-3 allows terminal 704-3 to receive anddemodulate transmission beam 702-2 for transmitting data of stream 1,and receiving directivity 706-3 allows terminal 704-3 to receive anddemodulate transmission beam 703-2 for transmitting data of stream 2.

Terminal 704-4 performs directivity control for receiving, via “signalprocessor 405” and/or “antennas 401-1 to 401-N” and/or “multipliers603-1 to 603-L and processor 605”, and forms receiving directivity 705-4and receiving directivity 706-4. Receiving directivity 705-4 allowsterminal 704-4 to receive and demodulate transmission beam 702-3 fortransmitting data of stream 1, and receiving directivity 706-4 allowsterminal 704-4 to receive and demodulate transmission beam 703-2 fortransmitting data of stream 2.

Terminal 704-5 performs directivity control for receiving, via “signalprocessor 405” and/or “antennas 401-1 to 401-N” and/or “multipliers603-1 to 603-L and processor 605”, and forms receiving directivity 705-5and receiving directivity 706-5. Receiving directivity 705-5 allowsterminal 704-5 to receive and demodulate transmission beam 702-3 fortransmitting data of stream 1, and receiving directivity 706-5 allowsterminal 704-5 to receive and demodulate transmission beam 703-3 fortransmitting data of stream 2.

In FIG. 7, a terminal selects, according to a spatial position, at leastone transmission beam from among transmission beams 702-1, 702-2, and702-3 for transmitting data of stream 1, and can obtain data of stream 1with high quality by directing a receiving directivity to the selectedtransmission beam(s). Furthermore, the terminal selects, according to aspatial position, at least one transmission beam from among transmissionbeams 703-1, 703-2, and 703-3 for transmitting data of stream 2, and canobtain data of stream 2 with high quality by directing a receivingdirectivity to the selected transmission beam(s).

Note that base station 700 transmits transmission beam 702-1 fortransmitting data of stream 1 and transmission beam 703-1 fortransmitting data of stream 2, using the same frequency (the samefrequency band) at the same time. Base station 700 transmitstransmission beam 702-2 for transmitting data of stream 1 andtransmission beam 703-2 for transmitting data of stream 2, using thesame frequency (the same frequency band) at the same time. Base station700 transmits transmission beam 702-3 for transmitting data of stream 1and transmission beam 703-3 for transmitting data of stream 2, using thesame frequency (the same frequency band) at the same time.

Transmission beams 702-1, 702-2, and 702-3 for transmitting data ofstream 1 may be beams having the same frequency (the same frequencyband) or may be beams having different frequencies (different frequencybands). Transmission beams 703-1, 703-2, and 703-3 for transmitting dataof stream 2 may be beams having the same frequency (the same frequencyband), or may be beams having different frequencies (different frequencybands).

A description of operation of setting unit 158 of the base station inFIGS. 1 and 3 is to be given.

Setting unit 158 receives an input of setting signal 160. Setting signal160 includes information with regard to “whether to perform transmissionfor multicasting or transmission for unicasting”, and if the basestation performs transmission as illustrated in FIG. 7, informationindicating “to perform transmission for multicasting” is input tosetting unit 158 according to setting signal 160.

Setting signal 160 includes information with regard to “the number oftransmission streams when multicasting is performed” and if the basestation performs transmission as illustrated in FIG. 7, informationindicating that “the number of transmission streams is 2” is input tosetting unit 158 according to setting signal 160.

Setting signal 160 may include information with regard to “how manytransmission beams are to be used to transmit each stream”. If the basestation performs transmission as illustrated in FIG. 7, informationindicating that “the number of transmission beams for transmittingstream 1 is 3 and the number of transmission beams for transmittingstream 2 is 3” is input to setting unit 158 according to setting signal160.

Note that the base station in FIGS. 1 and 3 may transmit a controlinformation symbol which includes, for instance, information with regardto “whether to perform transmission for multicasting or transmission forunicasting”, information with regard to “the number of transmissionstreams when multicasting is performed”, information with regard to “howmany transmission beams are to be used to transmit each stream”.Accordingly, a terminal can appropriately receive data. A configurationof a control information symbol will be later described in detail.

FIG. 8 is a drawing for describing a relation between #i information101-i in FIGS. 1 and 3 and “stream 1” and “stream 2” described withreference to FIG. 7. For example, processing such as error correctioncoding is performed on #1 information 101-1, and data obtained as aresult of the error correction coding is obtained. The data obtained asa result of the error correction coding is named #1 transmission data.Data symbols are obtained by mapping #1 transmission data. By separatingdata symbols into data symbols for stream 1 and data symbols for stream2, data symbols (data symbol group) for stream 1 and data symbols (datasymbol group) for stream 2 are obtained. The symbol group for stream 1includes data symbols (data symbol group) for stream 1, and istransmitted from the base station in FIGS. 1 and 3. The symbol group forstream 2 includes data symbols (data symbol group) for stream 2, and istransmitted from the base station in FIGS. 1 and 3.

FIG. 9 illustrates an example of a frame configuration when thehorizontal axis indicates time.

#1 symbol group 901-1 for stream 1 in FIG. 9 is a symbol group fortransmission beam 702-1 for transmitting data of stream 1 in FIG. 7.

#2 symbol group 901-2 for stream 1 in FIG. 9 is a symbol group fortransmission beam 702-2 for transmitting data of stream 1 in FIG. 7.

#3 symbol group 901-3 for stream 1 in FIG. 9 is a symbol group fortransmission beam 702-3 for transmitting data of stream 1 in FIG. 7.

#1 symbol group 902-1 for stream 2 in FIG. 9 is a symbol group fortransmission beam 703-1 for transmitting data of stream 2 in FIG. 7.

#2 symbol group 902-2 for stream 2 in FIG. 9 is a symbol group fortransmission beam 703-2 for transmitting data of stream 2 in FIG. 7.

#3 symbol group 902-3 for stream 2 in FIG. 9 is a symbol group fortransmission beam 703-3 for transmitting data of stream 2 in FIG. 7.

#1 symbol group 901-1 for stream 1, #2 symbol group 901-2 for stream 1,#3 symbol group 901-3 for stream 1, #1 symbol group 902-1 for stream 2,#2 symbol group 902-2 for stream 2, and #3 symbol group 902-3 for stream2 are present in time section 1, for example.

As described above, #1 symbol group 901-1 for stream 1 and #2 symbolgroup 902-1 for stream 2 are transmitted using the same frequency (thesame frequency band), #2 symbol group 901-2 for stream 1 and #2 symbolgroup 902-2 for stream 2 are transmitted using the same frequency (thesame frequency band), and #3 symbol group 901-3 for stream 1 and #3symbol group 902-3 for stream 2 are transmitted using the same frequency(the same frequency band).

For example, “data symbol group A for stream 1” and “data symbol group Afor stream 2” are generated from information, following the procedure inFIG. 8. The symbol group, namely “data symbol group A-1 for stream 1”which includes the same symbols as symbols included in “data symbolgroup A for stream 1”, the symbol group, namely “data symbol group A-2for stream 1” which includes the same symbols as symbols included in“data symbol group A for stream 1”, and the symbol group, namely “datasymbol group A-3 for stream 1” which includes the same symbols assymbols included in “data symbol group A for stream 1” are prepared.

Thus, the symbols included in “data symbol group A-1 for stream 1”, thesymbols included in “data symbol group A-2 for stream 1”, and thesymbols included in “data symbol group A-3 for stream 1” are the same.

At this time, #1 symbol group 901-1 for stream 1 in FIG. 9 includes“data symbol group A-1 for stream 1”, #2 symbol group 901-2 for stream 1in FIG. 9 includes “data symbol group A-2 for stream 1”, and #3 symbolgroup 901-3 for stream 1 in FIG. 9 includes “data symbol group A-3 forstream 1”. Accordingly, #1 symbol group 901-1 for stream 1, #2 symbolgroup 901-2 for stream 1, and #3 symbol group 901-3 for stream 1 includethe same data symbol group.

The symbol group, namely “data symbol group A-1 for stream 2” whichincludes the same symbols as symbols included in “data symbol group Afor stream 2”, the symbol group, namely “data symbol group A-2 forstream 2” which includes the same symbols as symbols included in “datasymbol group A for stream 2”, and the symbol group, namely “data symbolgroup A-3 for stream 2” which includes the same symbols as symbolsincluded in “data symbol group A for stream 2” are prepared.

Accordingly, the symbols included in “data symbol group A-1 for stream2”, the symbols included in “data symbol group A-2 for stream 2”, andthe symbols included in “data symbol group A-3 for stream 2” are thesame.

At this time, #1 symbol group 902-1 for stream 2 in FIG. 9 includes“data symbol group A-1 for stream 2”, #2 symbol group 902-2 for stream 2in FIG. 9 includes “data symbol group A-2 for stream 2”, and #3 symbolgroup 902-3 for stream 2 in FIG. 9 includes “data symbol group A-3 forstream 2”. Accordingly, #1 symbol group 902-1 for stream 2, #2 symbolgroup 902-2 for stream 2, and #3 symbol group 902-3 for stream 2 includethe same data symbol group.

FIG. 10 illustrates an example of a frame configuration of “symbol group#Y for stream X” (X=1, 2; Y=1, 2, 3) described with reference to FIG. 9.In FIG. 10, while the horizontal axis indicates time, 1001 denotes acontrol information symbol and 1002 denotes a data symbol group for astream. At this time, data symbol group 1002 for the stream includessymbols for transmitting “data symbol group A for stream 1” or “datasymbol group A for stream 2” described with reference to FIG. 9.

Note that a multi-carrier method such as the orthogonal frequencydivision multiplexing (OFDM) method may be used for the frameconfiguration in FIG. 10, and symbols may be present in the direction ofthe frequency axis, in this case. The symbols may include a referencesymbol for a receiving device to perform time synchronization andfrequency synchronization, a reference symbol for a receiving device todetect a signal, and a reference symbol for a receiving device toperform channel estimation, for instance. The frame configuration is notlimited to the configuration in FIG. 10, and control information symbol1001 and data symbol group 1002 for a stream may be arranged in anymanner. Note that the reference symbol may be referred to as a preambleand a pilot symbol.

The following describes a configuration of control information symbol1001.

FIG. 11 illustrates an example of a configuration of symbols transmittedas a control information symbol in FIG. 10, and the horizontal axisindicates time. In FIG. 11, a terminal receives “training symbol for aterminal to perform receiving directivity control” 1101 to determine asignal processing method for the directivity control for receiving,which is implemented by “signal processor 405” and/or “antennas 401-1 to401-N” and/or “multipliers 603-1 to 603-L and processor 605”.

A terminal receives “symbol for notifying the number of transmissionstreams when multicasting is performed” 1102 so that the terminal isinformed of the number of streams to be obtained.

A terminal receives “symbol for notifying for which stream data symbolsare” 1103 so that the terminal can be informed which stream has beensuccessfully received among the streams which the base station istransmitting.

A description of an example with regard to the above is to be given.

The case where the base station transmits streams using transmissionbeams as illustrated in FIG. 7 is to be described. Specific informationindicated by a control information symbol in #1 symbol group 901-1 forstream 1 in FIG. 9 is to be described.

In the case of FIG. 7, since the base station is transmitting “stream 1”and “stream 2”, information indicated by “symbol for notifying thenumber of transmission streams when multicasting is performed” 1102indicates “2”.

#1 symbol group 901-1 for stream 1 in FIG. 9 is for transmitting datasymbols for stream 1, and thus information indicated by “symbol fornotifying for which stream data symbols are” 1103 indicates “stream 1”.

The case where, for example, a terminal receives #1 symbol group 901-1for stream 1 in FIG. 9 is to be described. At this time, the terminalbecomes aware that “the number of transmission streams is 2” from“symbol for notifying the number of transmission streams whenmulticasting is performed” 1102, and that the terminal has obtained“data symbols for stream 1” from “symbol 1103 for notifying for whichstream data symbol group includes data symbols”.

After that, since the terminal becomes aware that “the number oftransmission streams is 2” and the obtained data symbols are “datasymbols for stream 1”, the terminal is aware that the terminal is toobtain “data symbols for stream 2”. Thus, the terminal can startoperation for searching for a symbol group for stream 2. For example,the terminal searches for one of transmission beams for transmitting #1symbol group 902-1 for stream 2, #2 symbol group 902-2 for stream 2, and#3 symbol group 902-3 for stream 2 in FIG. 9.

Then, the terminal obtains one of transmission beams for transmitting #1symbol group 902-1 for stream 2, #2 symbol group 902-2 for stream 2, and#3 symbol group 902-3 for stream 2, to obtain data symbols for bothstreams 1 and 2.

Configuring control information symbols in this manner yields anadvantageous effect that a terminal can obtain data symbols precisely.

As described above, the base station transmits data symbols using aplurality of transmission beams, and a terminal selectively receives atransmission beam with good quality among the plurality of transmissionbeams in multicast transmission and broadcast data transmission, andfurthermore, transmission directivity control and receiving directivitycontrol have been performed on modulated signals transmitted by the basestation, thus achieving advantageous effects of increasing an area wherehigh data receiving quality is achieved.

In the above description, a terminal performs receiving directivitycontrol, yet advantageous effects can be obtained as mentioned abovewithout the terminal performing receiving directivity control.

Note that the modulating method for “data symbol group for a stream”1002 in FIG. 10 may be any modulating method, and a mapping methodaccording to the modulating method for “data symbol group for a stream”1002 may be changed for each symbol. Accordingly, a phase of aconstellation may be changed for each symbol on an in-phase I-quadratureQ plane after mapping.

FIG. 12 illustrates an example of a state of communication between abase station and terminals different from the example in FIG. 7. Notethat elements which operate in the same manner as those in FIG. 7 areassigned the same reference numerals in FIG. 12.

Base station 700 includes a plurality of antennas, and transmits aplurality of transmission signals through antenna 701 for transmission.At this time, base station 700 has a configuration as illustrated in,for example, FIG. 1 or 3, and performs transmission beamforming(directivity control) by signal processor 102 (and/or weightingsynthesizer 301) performing precoding (weighting synthesis).

FIG. 12 illustrates transmission beam 1202-1 for transmitting “modulatedsignal 1”, transmission beam 1202-2 for transmitting “modulated signal1”, and transmission beam 1202-3 for transmitting “modulated signal 1”.

FIG. 12 illustrates transmission beam 1203-1 for transmitting “modulatedsignal 2”, transmission beam 1203-2 for transmitting “modulated signal2”, and transmission beam 1203-3 for transmitting “modulated signal 2”.

Note that although in FIG. 12, the number of transmission beams fortransmitting “modulated signal 1” is 3 and the number of transmissionbeams for transmitting “modulated signal 2” is 3, the present disclosureis not limited to such numbers, and the number of transmission beams fortransmitting “modulated signal 1” may be at least 2 and the number oftransmission beams for transmitting “modulated signal 2” may be at least2. A detailed description of “modulated signal 1” and “modulated signal2” will be given later.

FIG. 12 includes terminals 704-1, 704-2, 704-3, 704-4, and 704-5, andthe terminals have the same configuration as those in FIGS. 4 and 5, forexample.

For example, terminal 704-1 performs directivity control for receiving,via “signal processor 405” and/or “antennas 401-1 to 401-N” and/or“multipliers 603-1 to 603-L and processor 605”, and forms receivingdirectivity 705-1 and receiving directivity 706-1. Receiving directivity705-1 allows terminal 704-1 to receive and demodulate transmission beam1202-1 for transmitting “modulated signal 1”, and receiving directivity706-1 allows terminal 704-1 to receive and demodulate transmission beam1203-1 for transmitting “modulated signal 2”.

Similarly, terminal 704-2 performs directivity control for receiving,via “signal processor 405” and/or “antennas 401-1 to 401-N” and/or“multipliers 603-1 to 603-L and processor 605”, and forms receivingdirectivity 705-2 and receiving directivity 706-2. Receiving directivity705-2 allows terminal 704-2 to receive and demodulate transmission beam1202-1 for transmitting “modulated signal 1”, and receiving directivity706-2 allows terminal 704-2 to receive and demodulate transmission beam1203-1 for transmitting “modulated signal 2”.

Terminal 704-3 performs directivity control for receiving, via “signalprocessor 405” and/or “antennas 401-1 to 401-N” and/or “multipliers603-1 to 603-L and processor 605”, and forms receiving directivity 705-3and receiving directivity 706-3.

Receiving directivity 705-3 allows terminal 704-3 to receive anddemodulate transmission beam 1202-2 for transmitting “modulated signal1”, and receiving directivity 706-3 allows terminal 704-3 to receive anddemodulate transmission beam 1203-1 for transmitting “modulated signal2”.

Terminal 704-4 performs directivity control for receiving, via “signalprocessor 405” and/or “antennas 401-1 to 401-N” and/or “multipliers603-1 to 603-L and processor 605”, and forms receiving directivity 705-4and receiving directivity 706-4. Receiving directivity 705-4 allowsterminal 704-4 to receive and demodulate transmission beam 1202-3 fortransmitting “modulated signal 1”, and receiving directivity 706-4allows terminal 704-4 to receive and demodulate transmission beam 1203-2for transmitting “modulated signal 2”.

Terminal 704-5 performs directivity control for receiving, via “signalprocessor 405” and/or “antennas 401-1 to 401-N” and/or “multipliers603-1 to 603-L and processor 605”, and forms receiving directivity 705-5and receiving directivity 706-5. Receiving directivity 705-5 allowsterminal 704-5 to receive and demodulate transmission beam 1202-3 fortransmitting “modulated signal 1”, and receiving directivity 706-5allows terminal 704-5 to receive and demodulate transmission beam 1203-3for transmitting “modulated signal 2”.

Distinguishing points in FIG. 7 are that a terminal selects, based on aspatial position, at least one transmission beam from among transmissionbeams 1202-1, 1202-2, and 1202-3 for transmitting “modulated signal 1”,and can obtain “modulated signal 1” with high quality by directing areceiving directivity to the selected transmission beam(s). Further, theterminal selects, based on a spatial position, at least one transmissionbeam from among transmission beams 1203-1, 1203-2, and 1203-3 fortransmitting “modulated signal 2”, and can obtain “modulated signal 2”with high quality by directing a receiving directivity to the selectedtransmission beam(s).

Note that base station 700 transmits transmission beam 1202-1 fortransmitting “modulated signal 1” and transmission beam 1203-1 fortransmitting “modulated signal 2” using the same frequency (the samefrequency band) at the same time. Then, base station 700 transmitstransmission beam 1202-2 for transmitting “modulated signal 1” andtransmission beam 1203-2 for transmitting “modulated signal 2” using thesame frequency (the same frequency band) at the same time. Further, basestation 700 transmits transmission beam 1202-3 for transmitting“modulated signal 1” and transmission beam 1203-3 for transmitting“modulated signal 2” using the same frequency (the same frequency band)at the same time.

Transmission beams 1202-1, 1202-2, and 1202-3 for transmitting“modulated signal 1” may be beams having the same frequency (the samefrequency band) or may be beams having different frequencies (differentfrequency bands). Transmission beams 1203-1, 1203-2, and 1203-3 fortransmitting “modulated signal 2” may be beams having the same frequency(the same frequency band) or may be beams having different frequencies(different frequency bands).

A description of operation of setting unit 158 of the base station inFIGS. 1 and 3 is to be given.

Setting unit 158 receives an input of setting signal 160. Setting signal160 includes information with regard to “whether to perform transmissionfor multicasting or transmission for unicasting”, and if the basestation performs transmission as illustrated in FIG. 7, informationindicating “to perform transmission for multicasting” is input tosetting unit 158 according to setting signal 160.

Setting signal 160 includes information with regard to “the number oftransmission modulated signals when multicasting is performed” and ifthe base station performs transmission as illustrated in FIG. 12,information indicating that “the number of transmission modulatedsignals is 2” is input to setting unit 158 according to setting signal160.

Setting signal 160 may include information with regard to “how manytransmission beams are to be used to transmit each modulated signal”. Ifthe base station performs transmission as illustrated in FIG. 12,information indicating that “the number of transmission beams fortransmitting modulated signal 1 is 3 and the number of transmissionbeams for transmitting modulated signal 2 is 3” is input to setting unit158 according to setting signal 160.

Note that the base station in FIGS. 1 and 3 may transmit a controlinformation symbol which includes, for instance, information with regardto “whether to perform transmission for multicasting or transmission forunicasting”, information with regard to “the number of transmissionmodulated signals when multicasting is performed”, information withregard to “how many transmission beams are to be used to transmit eachmodulated signal”. Accordingly, a terminal can appropriately receivedata. A configuration of a control information symbol will be laterdescribed in detail.

FIG. 13 is a drawing for describing a relation between #i information101-i in FIGS. 1 and 3 and “modulated signal 1” and “modulated signal 2”described with reference to FIG. 12.

For example, #1 information 101-1 is subjected to error correctioncoding, for instance, and data obtained as a result of the errorcorrection coding is obtained. The data obtained as a result of theerror correction coding is named #1 transmission data. Data symbols areobtained by mapping #1 transmission data. The data symbols are separatedinto data symbols for stream 1 and data symbols for stream 2, so thatdata symbols (data symbol group) for stream 1 and data symbols (datasymbol group) for stream 2 are obtained. At this time, a data symbolhaving symbol number i for stream 1 is s1(i) and a data symbol havingsymbol number i for stream 2 is s2(i). Then, “modulated signal 1” tx1(i)having symbol number i is expressed as follows, for example.

[Math 3]

tx1(i)=α(i)×s1(i)+β(i)×s2(i)  Expression (3)

Then, “modulated signal 2” tx2(i) having symbol number i is expressed asfollows, for example.

[Math 4]

tx2(i)=γ(i)×s1(i)+δ(i)×s2(i)  Expression (4)

Note that in Expressions (3) and (4), α(i) can be defined by a complexnumber (and thus may be a real number), ß(i) can be defined by a complexnumber (and thus may be a real number), γ(i) can be defined by a complexnumber (and thus may be a real number), and δ(i) can be defined by acomplex number (and thus may be a real number). Furthermore, althoughα(i) is indicated, α(i) may not be a function of symbol number i (may bea fixed value), although ß(i) is indicated, ß(i) may not be a functionof symbol number i (may be a fixed value), although γ(i) is indicated,γ(i) may not be a function of symbol number i (may be a fixed value),and although δ(i) is indicated, δ(i) may not be a function of symbolnumber i (may be a fixed value).

Then, “a symbol group for modulated signal 1” which includes “signals ina data transmission area of modulated signal 1” which are constituted bydata symbols is transmitted from the base station in FIG. 1 or 3.Further, “a symbol group for modulated signal 2” which includes “signalsin a data transmission area of modulated signal 2” which are constitutedby data symbols is transmitted from the base station in FIG. 1 or 3.

Note that signal processing such as phase modification and cyclic delaydiversity (CDD) may be performed on “modulated signal 1” and “modulatedsignal 2”. Note that the method for signal processing is not limited tothose.

FIG. 14 illustrates an example of a frame configuration when thehorizontal axis indicates time.

#1 symbol group (1401-1) for modulated signal 1 in FIG. 14 is a symbolgroup for transmission beam 1202-1 for transmitting data of modulatedsignal 1 in FIG. 12.

#2 symbol group (1401-2) for modulated signal 1 in FIG. 14 is a symbolgroup for transmission beam 1202-2 for transmitting data of modulatedsignal 1 in FIG. 12.

#3 symbol group (1401-3) for modulated signal 1 in FIG. 14 is a symbolgroup for transmission beam 1202-3 for transmitting data of modulatedsignal 1 in FIG. 12.

#1 symbol group (1402-1) for modulated signal 2 in FIG. 14 is a symbolgroup for transmission beam 1203-1 for transmitting data of modulatedsignal 2 in FIG. 12.

#2 symbol group (1402-2) for modulated signal 2 in FIG. 14 is a symbolgroup for transmission beam 1203-2 for transmitting data of modulatedsignal 2 in FIG. 12.

#3 symbol group (1402-3) for modulated signal 2 in FIG. 14 is a symbolgroup for transmission beam 1203-3 for transmitting data of modulatedsignal 2 in FIG. 12.

#1 symbol group (1401-1) for modulated signal 1, #2 symbol group(1401-2) for modulated signal 1, #3 symbol group (1401-3) for modulatedsignal 1, #1 symbol group (1402-1) for modulated signal 2, #2 symbolgroup (1402-2) for modulated signal 2, and #3 symbol group (1402-3) formodulated signal 2 are present in time section 1, for example.

As previously described, #1 symbol group (1401-1) for modulated signal 1and #1 symbol group (1402-1) for modulated signal 2 are transmittedusing the same frequency (the same frequency band), #2 symbol group(1401-2) for modulated signal 1 and #2 symbol group (1402-2) formodulated signal 2 are transmitted using the same frequency (the samefrequency band), and #3 symbol group (1401-3) for modulated signal 1 and#3 symbol group (1402-3) for modulated signal 2 are transmitted usingthe same frequency (the same frequency band).

For example, “signal A in the data transmission area of modulated signal1” and “signal A in the data transmission area of modulated signal 2”are generated from information in accordance with the procedure in FIG.13.

“Signal A-1 in the data transmission area of modulated signal 1” whichis a signal constituted by a signal equivalent to a signal whichconstitutes “signal A in the data transmission area of modulated signal1”, “signal A-2 in the data transmission area of modulated signal 1”which is a signal constituted by a signal equivalent to a signal whichconstitutes “signal A in the data transmission area of modulated signal1”, and “signal A-3 in the data transmission area of modulated signal 1”which is a signal constituted by a signal equivalent to a signal whichconstitutes “signal A in the data transmission area of modulated signal1” are prepared (thus, the signal which constitutes “signal A-1 in thedata transmission area of modulated signal 1”, the signal whichconstitutes “signal A-2 in the data transmission area of modulatedsignal 1”, and the signal which constitutes “signal A-3 in the datatransmission area of modulated signal 1” are the same).

At this time, #1 symbol group (1401-1) for modulated signal 1 in FIG. 14includes “signal A-1 in the data transmission area of modulated signal1”, #2 symbol group (1401-2) for modulated signal 1 in FIG. 14 includes“signal A-2 in the data transmission area of modulated signal 1”, and #3symbol group (1401-3) for modulated signal 1 in FIG. 14 includes “signalA-3 in the data transmission area of modulated signal 1”. Specifically,#1 symbol group (1401-1) for modulated signal 1, #2 symbol group(1401-2) for modulated signal 1, and #3 symbol group (1401-3) formodulated signal 1 include equivalent signals.

Further, “signal A-1 in the data transmission area of modulated signal2” which is a signal constituted by a signal equivalent to a signalwhich constitutes “signal A in the data transmission area of modulatedsignal 2”, “signal A-2 in the data transmission area of modulated signal2” which is a signal constituted by a signal equivalent to a signalwhich constitutes “signal A in the data transmission area of modulatedsignal 2”, and “signal A-3 in the data transmission area of modulatedsignal 2” which is a signal constituted by a signal equivalent to asignal which constitutes “signal A in the data transmission area ofmodulated signal 2” are prepared (thus, the signal which constitutes“signal A-1 in the data transmission area of modulated signal 2”, thesignal which constitutes “signal A-2 in the data transmission area ofmodulated signal 2”, and the signal which constitutes “signal A-3 in thedata transmission area of modulated signal 2” are the same).

At this time, #1 symbol group (1402-1) for modulated signal 2 in FIG. 14includes “signal A-1 in the data transmission area of modulated signal2”, #2 symbol group (1402-2) for stream 2 in FIG. 14 includes “signalA-2 in the data transmission area of modulated signal 2”, and #3 symbolgroup (1402-3) for modulated signal 2 in FIG. 14 includes “signal A-3 inthe data transmission area of modulated signal 2”. Specifically, #1symbol group (1402-1) for modulated signal 2, #2 symbol group (1402-2)for modulated signal 2, and #3 symbol group (1402-3) for modulatedsignal 2 include equivalent signals.

FIG. 15 illustrates an example of a frame configuration of “symbol group#Y for modulated signal X” (X=1, 2; Y=1, 2, 3) described with referenceto FIG. 14. In FIG. 15, the horizontal axis indicates time, 1501indicates a control information symbol, and 1502 indicates a modulatedsignal transmission area for data transmission. At this time, modulatedsignal transmission area 1502 for data transmission includes symbols fortransmitting “signal A in the data transmission area of modulated signal1” or “signal A in the data transmission area of modulated signal 2”described with reference to FIG. 14.

Note that in the frame configuration in FIG. 15, a multi-carrier methodsuch as an orthogonal frequency division multiplexing (OFDM) method maybe used, and in this case, symbols may be present in the direction ofthe frequency axis. The symbols may each include a reference symbol fora receiving device to perform time synchronization and frequencysynchronization, a reference symbol for a receiving device to detect asignal, and a reference symbol for a receiving device to perform channelestimation, for instance. The frame configuration is not limited to theconfiguration in FIG. 15, and control information symbol 1501 andmodulated signal transmission area 1502 for data transmission may bearranged in any manner. A reference symbol may also be called a preambleand a pilot symbol, for example.

Next is a description of a configuration of control information symbol1501.

FIG. 16 illustrates an example of a configuration of symbols which areto be transmitted as a control information symbol in FIG. 15, and thehorizontal axis indicates time. In FIG. 16, 1601 denotes “a trainingsymbol for a terminal to perform receiving directivity control”, and theterminal determines a signal processing method for the directivitycontrol for receiving, which is performed by “signal processor 405”and/or “antennas 401-1 to 401-N” and/or “multipliers 603-1 to 603-L andprocessor 605”, by receiving “training symbol for a terminal to performreceiving directivity control” 1601.

1602 denotes “a symbol for notifying the number of transmissionmodulated signals when multicasting is performed”, and the terminal isinformed of the number of modulated signals which are to be obtained, byreceiving “symbol for notifying the number of transmission modulatedsignals when multicasting is performed” 1602.

1603 denotes “a symbol for notifying of which modulated signal amodulated signal transmission area for data transmission is”, and theterminal can be informed of which modulated signal has been successfullyreceived among modulated signals which the base station is transmitting,by receiving “symbol for notifying of which modulated signal a modulatedsignal transmission area for data transmission is” 1603.

An example of the above is to be described.

Now consider the case where the base station is transmitting “modulatedsignals” using transmission beams as illustrated in FIG. 12. Specificinformation on a control information symbol in #1 symbol group 1401-1for modulated signal 1 in FIG. 14 is to be described.

In the case of FIG. 12, the base station is transmitting “modulatedsignal 1” and “modulated signal 2”, and thus information indicated by“symbol for notifying the number of transmission modulated signals whenmulticasting is performed” 1602 is “2”.

#1 symbol group 1401-1 for modulated signal 1 in FIG. 14 is fortransmitting a signal in the data transmission area of modulated signal1, and thus information indicated by “symbol for notifying of whichmodulated signal a modulated signal transmission area for datatransmission is” 1603 indicates “modulated signal 1”.

For example, a terminal is assumed to receive #1 symbol group 1401-1 formodulated signal 1 in FIG. 14. At this time, the terminal becomes awarethat “the number of modulated signals is 2” is obtained from “symbol fornotifying the number of transmission modulated signals when multicastingis performed” 1602, and that “modulated signal 1” from “symbol fornotifying of which modulated signal a modulated signal transmission areafor data transmission is” 1603.

The terminal then becomes aware that “the number of present modulatedsignals is 2” and that the obtained modulated signal is “modulatedsignal 1”, and thus the terminal is aware that “modulated signal 2” isto be obtained. Accordingly, the terminal can start operation ofsearching for “modulated signal 2”. The terminal searches for one oftransmission beams for any of “#1 symbol group 1402-1 for modulatedsignal 2”, “#2 symbol group 1402-2 for modulated signal 2”, “#3 symbolgroup 1402-3 for modulated signal 2” in FIG. 14, for example.

The terminal obtains both “modulated signal 1” and “modulated signal 2”,and can obtain data symbols for stream 1 and data symbols for stream 2with high quality, by obtaining one transmission beam for “#1 symbolgroup 1402-1 for modulated signal 2”, “#2 symbol group 1402-2 formodulated signal 2”, and “#3 symbol group 1402-3 for modulated signal2”.

Configuring a control information symbol in the above manner yieldsadvantageous effects that the terminal can precisely obtain datasymbols.

As described above, in multicast data transmission and broadcast datatransmission, the base station transmits data symbols using a pluralityof transmission beams, and a terminal selectively receives atransmission beam with good quality among the plurality of transmissionbeams, thus achieving advantageous effects that a modulated signal whichthe base station has transmitted increases an area where high datareceiving quality is achieved. This is because the base station performstransmission directivity control and receiving directivity control.

In the above description, a terminal performs receiving directivitycontrol, yet advantageous effects can be obtained as mentioned abovewithout the terminal performing receiving directivity control.

Note that the case where each terminal obtains both a modulated signalof stream 1 and a modulated signal of stream 2 is described withreference to FIG. 7, yet the present disclosure is not limited to suchan embodiment. For example, an embodiment in which a modulated signaldesired to be obtained varies depending on a terminal may be achieved asin a case where there are a terminal which desires to obtain a modulatedsignal of stream 1, a terminal which desires to obtain a modulatedsignal of stream 2, and a terminal which desires to obtain both amodulated signal of stream 1 and a modulated signal of stream 2.

Embodiment 2

Embodiment 1 has described a method in which a base station transmitsdata symbols using a plurality of transmission beams in multicast datatransmission and broadcast data transmission. The present embodimentdescribes, as a variation of Embodiment 1, the case where a base stationperforms unicast data transmission as well as multicast datatransmission and broadcast data transmission.

FIG. 17 illustrates an example of a state of communication between thebase station (or an access point, for instance) and terminals. Elementswhich operate in the same manner as those in FIG. 7 are assigned thesame reference numerals, and a detailed description thereof is omitted.

Base station 700 includes a plurality of antennas, and transmits aplurality of transmission signals through antenna 701 for transmission.At this time, base station 700 has a configuration as illustrated in,for example, FIG. 1 or 3, and performs transmission beamforming(directivity control) by signal processor 102 (and/or weightingsynthesizer 301) performing precoding (weighting synthesis).

Then, transmission beams 702-1, 702-2, 702-3, 703-1, 703-2, and 703-3are as described with reference to FIG. 7, and thus a descriptionthereof is omitted.

Terminals 704-1, 704-2, 704-3, 704-4, and 704-5, and receivingdirectivities 705-1, 705-2, 705-3, 705-4, 705-5, 706-1, 706-2, 706-3,706-4, and 706-5 are as described with reference to FIG. 7, and thus adescription thereof is omitted.

In FIG. 17, a distinguishing point is that the base station performsmulticasting, as described with reference to FIG. 7, and also basestation 700 and a terminal (for example, 1702) perform unicastcommunication.

In addition to transmission beams for multicasting 702-1, 702-2, 702-3,703-1, 703-2, and 703-3, in FIG. 17, base station 700 generatestransmission beam 1701 for unicasting, and transmits to terminal 1702data therefor. Note that FIG. 17 illustrates an example in which basestation 700 transmits one transmission beam 1702 to terminal 1702. Yet,the number of transmission beams is not limited to one, and base station700 may transmit a plurality of transmission beams to terminal 1702 (maytransmit a plurality of modulated signals).

Terminal 1702 performs directivity control for receiving, via “signalprocessor 405” and/or “antennas 401-1 to 401-N” and/or “multipliers603-1 to 603-L and signal processor 605”, and forms receivingdirectivity 1703. This allows terminal 1702 to receive and demodulatetransmission beam 1701.

Note that in order to generate transmission beams which includetransmission beam 1701, the base station performs precoding (weightingsynthesis) using signal processor 102 (and/or weighting synthesizer 301)in the configuration as illustrated in FIG. 1 or 3, for example.

On the contrary, when terminal 1702 transmits a modulated signal to basestation 700, the terminal performs precoding (or weighting synthesis),and transmits transmission beam 1703. Base station 700 performsdirectivity control for receiving and forms receiving directivity 1701.Accordingly, base station 700 can receive and demodulate transmissionbeam 1703.

Note that base station 700 transmits transmission beam 702-1 fortransmitting data of stream 1 and transmission beam 703-1 fortransmitting data of stream 2, using the same frequency (the samefrequency band) at the same time. Base station 700 transmitstransmission beam 702-2 for transmitting data of stream 1 andtransmission beam 703-2 for transmitting data of stream 2, using thesame frequency (the same frequency band) at the same time. Further, basestation 700 transmits transmission beam 702-3 for transmitting data ofstream 1 and transmission beam 703-3 for transmitting data of stream 2,using the same frequency (the same frequency band) at the same time.

Transmission beams 702-1, 702-2, and 702-3 for transmitting data ofstream 1 may be beams having the same frequency (the same frequencyband), or may be beams having different frequencies (different frequencybands). Transmission beams 703-1, 703-2, and 703-3 for transmitting dataof stream 2 may be beams having the same frequency (the same frequencyband), or may be beams having different frequencies (different frequencybands).

Then, transmission beam 1701 for unicasting may be a beam having thesame frequency (the same frequency band) as or a different frequency (adifferent frequency band) from those of transmission beams 702-1, 702-2,702-3, 703-1, 703-2, and 703-3.

A description has been given with reference to FIG. 17, assuming that aterminal which performs unicast communication is a single terminal, yetthe number of terminals which perform unicast communication with thebase station may be two or more.

Operation of setting unit 158 at this time in the base station havingthe configuration illustrated in FIG. 1 or 3 is described.

Setting unit 158 receives an input of setting signal 160. Setting signal160 includes information with regard to “whether to perform transmissionfor multicasting or transmission for unicasting”, and if the basestation performs transmission as illustrated in FIG. 17, informationindicating “to perform both transmission for multicasting andtransmission for unicasting” is input to setting unit 158 according tosetting signal 160.

Also, setting signal 160 includes information with regard to “the numberof transmission streams when multicasting is performed” and if the basestation performs transmission as illustrated in FIG. 17, informationindicating that “the number of transmission streams is 2” is input tosetting unit 158 according to setting signal 160.

Setting signal 160 may include information with regard to “how manytransmission beams are to be used to transmit each stream”. If the basestation performs transmission as illustrated in FIG. 17, informationindicating that “the number of transmission beams for transmittingstream 1 is 3 and the number of transmission beams for transmittingstream 2 is 3” is input to setting unit 158 according to setting signal160.

Note that the base station in FIGS. 1 and 3 may transmit a controlinformation symbol which includes information with regard to “whether toperform transmission for multicasting or transmission for unicasting”,information with regard to “the number of transmission streams whenmulticasting is performed”, information with regard to “how manytransmission beams are to be used to transmit each stream”, and others.Accordingly, a terminal can appropriately receive data.

Furthermore, the base station may transmit, to a terminal with which thebase station performs unicast communication, a control informationsymbol for training for the base station to perform directivity control,and a control information symbol for training for a terminal to performdirectivity control.

FIG. 18 illustrates an example of a state of communication between abase station (or an access point or the like) and terminals, andelements which operate in the same manner as those in FIGS. 7 and 12 areassigned the same reference numerals in FIG. 18, and a detaileddescription thereof is omitted.

Base station 700 includes a plurality of antennas, and transmits aplurality of transmission signals from antenna 701 for transmission. Atthis time, base station 700 has a configuration as illustrated in, forexample, FIG. 1 or 3, and performs transmission beamforming (directivitycontrol) by signal processor 102 (and/or weighting synthesizer 301)performing precoding (weighting synthesis).

A description of transmission beams 1202-1, 1202-2, 1202-3, 1203-1,1203-2, and 1203-3 is as described with reference to FIG. 12, and thus adescription thereof is omitted.

A description of terminals 704-1, 704-2, 704-3, 704-4, and 704-5, andreceiving directivities 705-1, 705-2, 705-3, 705-4, 705-5, 706-1, 706-2,706-3, 706-4, and 706-5 is as given with reference to FIG. 12, and thusa description thereof is omitted.

A distinguishing point in FIG. 18 is that while the base stationperforms multicasting, base station 700 and a terminal (for example,1702) perform unicast communication.

In FIG. 18, base station 700 generates transmission beam 1701 forunicasting in addition to transmission beams 1202-1, 1202-2, 1202-3,1203-1, 1203-2, and 1203-3 for multicasting, and transmits to terminal1702 data therefor. Note that FIG. 18 illustrates an example in whichbase station 700 transmits one transmission beam 1701 to terminal 1702,yet the number of transmission beams is not limited to one, and basestation 700 may transmit a plurality of transmission beams to terminal1702 (may transmit a plurality of modulated signals).

Terminal 1702 performs directivity control for receiving, via “signalprocessor 405” and/or “antennas 401-1 to 401-N” and/or “multipliers603-1 to 603-L and signal processor 605”, and forms receivingdirectivity 1703. Accordingly, terminal 1702 can receive and demodulatetransmission beam 1701.

Note that in order to generate transmission beams which includetransmission beam 1701, the base station performs precoding (weightingsynthesis) in signal processor 102 (and/or, weighting synthesizer 301)in the configuration as illustrated in, for example, FIG. 1 or 3.

On the contrary, when terminal 1702 transmits a modulated signal to basestation 700, the terminal performs precoding (or weighting synthesis),and transmits transmission beam 1703, and base station 700 performsdirectivity control for receiving, and forms receiving directivity 1701.Accordingly, base station 700 can receive and demodulate transmissionbeam 1703.

Note that base station 700 transmits transmission beam 1202-1 fortransmitting “modulated signal 1” and transmission beam 1203-1 fortransmitting “modulated signal 2”, using the same frequency (the samefrequency band) at the same time. Then, base station 700 transmitstransmission beam 1202-2 for transmitting “modulated signal 1” andtransmission beam 1203-2 for transmitting “modulated signal 2”, usingthe same frequency (the same frequency band) at the same time. Further,base station 700 transmits transmission beam 1202-3 for transmitting“modulated signal 1” and transmission beam 1203-3 for transmitting“modulated signal 2”, using the same frequency (the same frequency band)at the same time.

Transmission beams 1202-1, 1202-2, and 1202-3 for transmitting“modulated signal 1” may be beams having the same frequency (the samefrequency band) or may be beams having different frequencies (differentfrequency bands). Transmission beams 1203-1, 1203-2, and 1203-3 fortransmitting “modulated signal 2” may be beams having the same frequency(the same frequency band) or may be beams having different frequencies(different frequency bands).

Transmission beam 1701 for unicasting may be a beam having the samefrequency (the same frequency band) as or a different frequency(different frequency band) from those of transmission beams 1202-1,1202-2, 1202-3, 1203-1, 1203-2, and 1203-3.

A description has been given with reference to FIG. 18, assuming that aterminal which performs unicast communication is a single terminal, yetthe number of terminals which perform unicast communication with thebase station may be two or more.

Operation of setting unit 158 at this time in the base station havingthe configuration illustrated in FIG. 1 or 3 is described.

Setting unit 158 receives an input of setting signal 160. Setting signal160 includes information with regard to “whether to perform transmissionfor multicasting or transmission for unicasting”, and if the basestation performs transmission as illustrated in FIG. 18, informationindicating “to perform both transmission for multicasting andtransmission for unicasting” is input to setting unit 158 according tosetting signal 160.

Setting signal 160 also includes information with regard to “the numberof transmission streams when multicasting is performed” and if the basestation performs transmission as illustrated in FIG. 18, informationindicating that “the number of transmission streams is 2” is input tosetting unit 158 according to setting signal 160.

Setting signal 160 may include information with regard to “how manytransmission beams are to be used to transmit each stream”. If the basestation performs transmission as illustrated in FIG. 18, informationindicating that “the number of transmission beams for transmittingstream 1 is 3 and the number of transmission beams for transmittingstream 2 is 3” is input to setting unit 158 according to setting signal160.

Note that the base station in FIGS. 1 and 3 may transmit a controlinformation symbol which includes information with regard to “whether toperform transmission for multicasting or transmission for unicasting”,information with regard to “the number of transmission streams whenmulticasting is performed”, and information with regard to “how manytransmission beams are to be used to transmit each stream”, forinstance. Accordingly, a terminal can appropriately receive data.

Furthermore, the base station may transmit, to a terminal with which thebase station performs unicast communication, a control informationsymbol for training for the base station to perform directivity control,and a control information symbol for training for a terminal to performdirectivity control.

The following describes the case where the base station transmits aplurality of data by multicasting, as a variation of Embodiment 1.

FIG. 19 illustrates an example of a state of communication between thebase station (or an access point, for instance) and terminals, andelements which operate in the same manner as those in FIG. 7 areassigned the same reference numerals in FIG. 19, so that a detaileddescription thereof is omitted.

Base station 700 includes a plurality of antennas, and transmits aplurality of transmission signals through antenna 701 for transmission.At this time, base station 700 has a configuration as illustrated in,for example, FIG. 1 or 3, and performs transmission beamforming(directivity control) by signal processor 102 (and/or weightingsynthesizer 301) performing precoding (weighting synthesis).

A description of transmission beams 702-1, 702-2, 702-3, 703-1, 703-2,and 703-3 is as given with reference to FIG. 7, and thus a descriptionthereof is omitted.

A description of terminals 704-1, 704-2, 704-3, 704-4, and 704-5 andreceiving directivities 705-1, 705-2, 705-3, 705-4, 705-5, 706-1, 706-2,706-3, 706-4, and 706-5 is as described with reference to FIG. 7, andthus a description thereof is omitted.

Base station 700 transmits transmission beams 1901-1, 1901-2, 1902-1,and 1902-2, in addition to transmission beams 702-1, 702-2, 702-3,703-1, 703-2, and 703-3.

Transmission beam 1901-1 is a transmission beam for transmitting data ofstream 3. Transmission beam 1901-2 is also a transmission beam fortransmitting data of stream 3.

Transmission beam 1902-1 is a transmission beam for transmitting data ofstream 4. Transmission beam 1902-2 is also a transmission beam fortransmitting data of stream 4.

Reference numerals 704-1, 704-2, 704-3, 704-4, 704-5, 1903-1, 1903-2,and 1903-3 denote terminals, and each have a configuration asillustrated in FIGS. 4 and 5, for example. Note that operation ofterminals 704-1, 704-2, 704-3, 704-4, and 704-5 is as described withreference to FIG. 7.

Terminal 1903-1 performs directivity control for receiving, via “signalprocessor 405” and/or “antennas 401-1 to 401-N” and/or “multipliers603-1 to 603-L and processor 605”, and forms receiving directivity1904-1 and receiving directivity 1905-1. Receiving directivity 1904-1allows terminal 1903-1 to receive and demodulate transmission beam1901-2 for transmitting data of stream 3, and receiving directivity1905-1 allows terminal 1903-1 to receive and demodulate transmissionbeam 1902-2 for transmitting data of stream 4.

Terminal 1903-2 performs directivity control for receiving, via “signalprocessor 405” and/or “antennas 401-1 to 401-N” and/or “multipliers603-1 to 603-L and processor 605”, and forms receiving directivity1904-2 and receiving directivity 1905-2. Receiving directivity 1904-2allows terminal 1903-2 to receive and demodulate transmission beam1902-1 for transmitting data of stream 4, and receiving directivity1905-2 allows terminal 1903-2 to receive and demodulate transmissionbeam 1901-2 for transmitting data of stream 3.

Terminal 1903-3 performs directivity control for receiving, via “signalprocessor 405” and/or “antennas 401-1 to 401-N” and/or “multipliers603-1 to 603-L and processor 605”, and forms receiving directivity1904-3 and receiving directivity 1905-3. Receiving directivity 1904-3allows terminal 1903-3 to receive and demodulate transmission beam1901-1 for transmitting data of stream 3, and receiving directivity1905-3 allows terminal 1903-3 to receive and demodulate transmissionbeam 1902-1 for transmitting data of stream 4.

Terminal 1903-4 performs directivity control for receiving, via “signalprocessor 405” and/or “antennas 401-1 to 401-N” and/or “multipliers603-1 to 603-L and processor 605”, and forms receiving directivity1904-4 and receiving directivity 1905-4. Receiving directivity 1904-4allows terminal 1903-4 to receive and demodulate transmission beam 703-1for transmitting data of stream 2, and receiving directivity 1905-4allows terminal 1903-4 to receive and demodulate transmission beam1901-1 for transmitting data of stream 3.

In FIG. 19, a distinguishing point is that the base station transmits aplurality of streams each including data for multicasting, and alsotransmits each stream using a plurality of transmission beams, and eachterminal selectively receives one or more transmission beams for onemore streams among a plurality of streams.

Note that base station 700 transmits transmission beam 702-1 fortransmitting data of stream 1 and transmission beam 703-1 fortransmitting data of stream 2, using the same frequency (the samefrequency band) at the same time. Base station 700 transmitstransmission beam 702-2 for transmitting data of stream 1 andtransmission beam 703-2 for transmitting data of stream 2, using thesame frequency (the same frequency band) at the same time. Further, basestation 700 transmits transmission beam 702-3 for transmitting data ofstream 1 and transmission beam 703-3 for transmitting data of stream 2,using the same frequency (the same frequency band) at the same time.

Base station 700 transmits transmission beam 1901-1 for transmittingdata of stream 3 and transmission beam 1902-1 for transmitting data ofstream 4, using the same frequency (the same frequency band) at the sametime.

Base station 700 transmits transmission beam 1901-2 for transmittingdata of stream 3 and transmission beam 1902-2 for transmitting data ofstream 4, using the same frequency (the same frequency band) at the sametime.

Transmission beams 702-1, 702-2, and 702-3 for transmitting data ofstream 1 may be beams having the same frequency (the same frequencyband), or may be beams having different frequencies (different frequencybands). Transmission beams 703-1, 703-2, and 703-3 for transmitting dataof stream 2 may be beams having the same frequency (the same frequencyband), or may be beams having different frequencies (different frequencybands).

Transmission beams 1901-1 and 1901-2 for transmitting data of stream 3may be beams having the same frequency (the same frequency band), or maybe beams having different frequencies (different frequency bands).Transmission beams 1902-1 and 1902-2 for transmitting data of stream 4may be beams having the same frequency (the same frequency band), or maybe beams having different frequencies (different frequency bands).

Then, data symbols for stream 1 and data symbols for stream 2 may begenerated from #1 information 101-1 in FIG. 1, and data symbols forstream 3 and data symbols for stream 4 may be generated from #2information 101-2. Note that error correction coding may be performed oneach of #1 information 101-1 and #2 information 101-2, and thereafterdata symbols may be generated therefrom.

Data symbols for stream 1 may be generated from #1 information 101-1 inFIG. 1, data symbols for stream 2 may be generated from #2 information101-2 in FIG. 1, data symbols for stream 3 may be generated from #3information 101-3 in FIG. 1, and data symbols for stream 4 may begenerated from #4 information 101-4 in FIG. 1. Note that errorcorrection coding may be performed on each of #1 information 101-1, #2information 101-2, #3 information 101-3, and #4 information 101-4, andthereafter data symbols may be generated therefrom.

Specifically, data symbols for streams may be generated from any of theinformation in FIG. 1. This yields advantageous effect that a terminalcan selectively obtain a stream for multicasting.

Operation of setting unit 158 at this time in the base station havingthe configuration illustrated in FIG. 1 or 3 is to be described.

Setting unit 158 receives an input of setting signal 160. Setting signal160 includes information with regard to “whether to perform transmissionfor multicasting or transmission for unicasting”, and if the basestation performs transmission as illustrated in FIG. 19, informationindicating “to perform transmission for multicasting” is input tosetting unit 158 according to setting signal 160.

Setting signal 160 includes information with regard to “the number oftransmission streams when multicasting is performed” and if the basestation performs transmission as illustrated in FIG. 19, informationindicating that “the number of transmission streams is 4” is input tosetting unit 158 according to setting signal 160.

Setting signal 160 may include information with regard to “how manytransmission beams are to be used to transmit each stream”. If the basestation performs transmission as illustrated in FIG. 19, informationindicating that “the number of transmission beams for transmittingstream 1 is 3, the number of transmission beams for transmitting stream2 is 3, the number of transmission beams for transmitting stream 3 is 2,and the number of transmission beams for transmitting stream 4 is 2” isinput to setting unit 158 according to setting signal 160.

Note that the base station in FIGS. 1 and 3 may transmit a controlinformation symbol which includes, for instance, information with regardto “whether to perform transmission for multicasting or transmission forunicasting”, information with regard to “the number of transmissionstreams when multicasting is performed”, and information with regard to“how many transmission beams are to be used to transmit each stream”.Accordingly, a terminal can appropriately receive data.

The following describes the case where the base station transmits aplurality of data by multicasting, as a variation of Embodiment 1.

FIG. 20 illustrates an example of a state of communication between thebase station (or an access point, for instance) and terminals, andelements which operate in the same manner as those in FIGS. 7, 12, and19 are assigned the same reference numerals in FIG. 20, so that adetailed description thereof is omitted.

Base station 700 includes a plurality of antennas, and transmits aplurality of transmission signals from antenna 701 for transmission. Atthis time, base station 700 has a configuration as illustrated in, forexample, FIG. 1 or 3, and performs transmission beamforming (directivitycontrol) by signal processor 102 (and/or weighting synthesizer 301)performing precoding (weighting synthesis).

A description of transmission beams 1202-1, 1202-2, 1202-3, 1203-1,1203-2, and 1203-3 overlaps a description given with reference to FIG.12, and thus a description thereof is omitted.

A description of terminals 704-1, 704-2, 704-3, 704-4, and 704-5, andreceiving directivity 705-1, 705-2, 705-3, 705-4, 705-5, 706-1, 706-2,706-3, 706-4, and 706-5 overlaps a description given with reference toFIG. 12, and thus a description thereof is omitted.

Base station 700 transmits transmission beams 2001-1, 2001-2, 2002-1,and 2002-2, in addition to transmission beams 1202-1, 1202-2, 1202-3,1203-1, 1203-2, and 1203-3.

Transmission beam 2001-1 is a transmission beam for transmitting“modulated signal 3”. Transmission beam 2001-2 is also a transmissionbeam for transmitting “modulated signal 3”.

Transmission beam 2002-1 is a transmission beam for transmitting“modulated signal 4”. Transmission beam 2002-2 is also a transmissionbeam for transmitting “modulated signal 4”.

Terminals 704-1, 704-2, 704-3, 704-4, 704-5, 1903-1, 1903-2, and 1903-3have the same configuration as those illustrated in FIGS. 4 and 5, forexample. Note that operation of terminals 704-1, 704-2, 704-3, 704-4,and 704-5 is the same as a description given with reference to FIG. 7.

Terminal 1903-1 performs directivity control for receiving, via “signalprocessor 405” and/or “antennas 401-1 to 401-N” and/or “multipliers603-1 to 603-L and processor 605”, and forms receiving directivity1904-1 and receiving directivity 1905-1. Receiving directivity 1904-1allows terminal 1903-1 to receive and demodulate transmission beam2001-2 for transmitting “modulated signal 3”, and receiving directivity1905-1 allows terminal 1903-1 to receive and demodulate transmissionbeam 2002-2 for transmitting “modulated signal 4”.

Terminal 1903-2 performs directivity control for receiving, via “signalprocessor 405” and/or “antennas 401-1 to 401-N” and/or “multipliers603-1 to 603-L and processor 605”, and forms receiving directivity1904-2 and receiving directivity 1905-2. Receiving directivity 1904-2allows terminal 1903-2 to receive and demodulate transmission beam2002-1 for transmitting “modulated signal 4”, and receiving directivity1905-2 allows terminal 1903-2 to receive and demodulate transmissionbeam 2001-2 for transmitting “modulated signal 3”.

Terminal 1903-3 performs directivity control for receiving, via “signalprocessor 405” and/or “antennas 401-1 to 401-N” and/or “multipliers603-1 to 603-L and processor 605”, and forms receiving directivity1904-3 and receiving directivity 1905-3. Receiving directivity 1904-3allows terminal 1903-3 to receive and demodulate transmission beam2001-1 for transmitting “modulated signal 3”, and receiving directivity1905-3 allows terminal 1903-3 to receive and demodulate transmissionbeam 2002-1 for transmitting “modulated signal 4”.

Terminal 1903-4 performs directivity control for receiving, via “signalprocessor 405” and/or “antennas 401-1 to 401-N” and/or “multipliers603-1 to 603-L and processor 605”, and forms receiving directivity1904-4 and receiving directivity 1905-4. Receiving directivity 1904-4allows terminal 1903-4 to receive and demodulate transmission beam2001-1 for transmitting “modulated signal 3”, and receiving directivity1905-4 allows terminal 1903-4 to receive and demodulate transmissionbeam 2002-1 for transmitting “modulated signal 4”.

In FIG. 20, the base station transmits a plurality of modulated signalseach including data for multicasting, and transmits each modulatedsignal using a plurality of transmission beams. Each terminalselectively receives one or more transmission beams used to transmit oneor more streams among the plurality of modulated signals.

Note that base station 700 transmits transmission beam 1202-1 fortransmitting “modulated signal 1” and transmission beam 1203-1 fortransmitting “modulated signal 2”, using the same frequency (the samefrequency band) at the same time. Then, base station 700 transmitstransmission beam 1202-2 for transmitting “modulated signal 1” andtransmission beam 1203-2 for transmitting “modulated signal 2”, usingthe same frequency (the same frequency band) at the same time. Further,base station 700 transmits transmission beam 1202-3 for transmitting“modulated signal 1” and transmission beam 1203-3 for transmitting“modulated signal 2”, using the same frequency (the same frequency band)at the same time.

Base station 700 transmits transmission beam 2001-1 for transmitting“modulated signal 3” and transmission beam 2002-1 for transmitting“modulated signal 4”, using the same frequency (the same frequency band)at the same time. Then, base station 700 transmits transmission beam2001-2 for transmitting “modulated signal 3” and transmission beam2002-2 for transmitting “modulated signal 4”, using the same frequency(the same frequency band) at the same time.

Transmission beams 702-1, 702-2, and 702-3 for transmitting data ofstream 1 may be beams having the same frequency (the same frequencyband), or may be beams having different frequencies (different frequencybands). Transmission beams 703-1, 703-2, and 703-3 for transmitting dataof stream 2 may be beams having the same frequency (the same frequencyband), or may be beams having different frequencies (different frequencybands).

Transmission beams 2001-1 and 2001-2 for transmitting “modulated signal3” may be beams having the same frequency (the same frequency band) ormay be beams having different frequencies (different frequency bands).Transmission beams 2002-1 and 2002-2 for transmitting “modulated signal4” may be beams having the same frequency (the same frequency band) ormay be beams having different frequencies (different frequency bands).

Operation of setting unit 158 at this time in the base station havingthe configuration illustrated in FIG. 1 or 3 is to be described.

Setting unit 158 receives an input of setting signal 160. Setting signal160 includes information with regard to “whether to perform transmissionfor multicasting or transmission for unicasting”, and if the basestation performs transmission illustrated in FIG. 19, informationindicating “to perform transmission for multicasting” is input tosetting unit 158 according to setting signal 160.

Setting signal 160 includes information with regard to “the number oftransmission modulated signals when multicasting is performed”, and ifthe base station performs transmission illustrated in FIG. 20,information indicating “the number of transmission modulated signals is4” is input to setting unit 158 according to setting signal 160.

Setting signal 160 may include information with regard to “how manytransmission beams are to be used to transmit each modulated signal”.When the base station performs transmission illustrated in FIG. 20,information indicating that “the number of transmission beams fortransmitting modulated signal 1 is 3, the number of transmission beamsfor transmitting modulated signal 2 is 3, the number of transmissionbeams for transmitting modulated signal 3 is 2, and the number oftransmission beams for transmitting modulated signal 4 is 2” is input tosetting unit 158 according to setting signal 160.

Note that the base station in FIGS. 1 and 3 may transmit a controlinformation symbol which includes, for instance, information with regardto “whether to perform transmission for multicasting or transmission forunicasting”, information with regard to “the number of transmissionstreams when multicasting is performed”, information with regard to “howmany transmission beams are to be used to transmit each stream”.Accordingly, a terminal can appropriately receive data.

Note that in FIG. 20, if a terminal receives both a transmission beamfor “modulated signal 1”, and a transmission beam for “modulated signal2”, the terminal can obtain data of stream 1 and data of stream 2 withhigh receiving quality.

Similarly, if a terminal receives both a transmission beam for“modulated signal 3”, and a transmission beam for “modulated signal 4”,the terminal can obtain data of stream 3 and data of stream 4 with highreceiving quality.

FIG. 20 illustrates an example in which the base station transmits“modulated signal 1”, “modulated signal 2”, “modulated signal 3”, and“modulated signal 4”, yet the base station may transmit “modulatedsignal 5” and “modulated signal 6” for transmitting data of stream 5 anddata of stream 6, respectively, and may transmit more modulated signalsin order to transmit more streams. Note that the base station transmitseach of the modulated signals using one or more transmission beams.

Furthermore, as described with reference to FIGS. 17 and 18, one or moretransmission beams for unicasting (or receiving directivity control) maybe present.

A description of a relation between “modulated signal 1” and “modulatedsignal 2” overlaps a description with reference to FIG. 13, and thus thedescription thereof is omitted. Here, a description of a relationbetween “modulated signal 3” and “modulated signal 4” is given withreference to FIG. 21.

For example, #2 information 101-2 is subjected to processing such aserror correction coding, and data obtained as a result of the errorcorrection coding is obtained. The data obtained as a result of theerror correction coding is named #2 transmission data. Data symbols areobtained by mapping #2 transmission data. The data symbols are separatedinto data symbols for stream 3 and data symbols for stream 4, so thatdata symbols (data symbol group) for stream 3 and data symbols (datasymbol group) for stream 4 are obtained. At this time, a data symbolhaving symbol number i for stream 3 is s3(i), and a data symbol havingsymbol number i for stream 4 is s4(i). Then, “modulated signal 3” t×3(i)having symbol number i is expressed as follows, for example.

[Math 5]

tx3(i)=e(i)×s3(i)+f(i)×s4(i)  Expression (5)

Then, “modulated signal 4” t×4(i) having symbol number i is expressed asfollows, for example.

[Math 6]

tx4(i)=g(i)×s3(i)+h(i)×s4(i)  Expression (6)

Note that e(i), f(i), g(i), and h(i) in Expressions (5) and (6) can bedefined by complex numbers, and thus may be real numbers.

Although e(i), f(i), g(i), and h(i) are indicated, e(i), f(i), g(i), andh(i) may not be functions of symbol number i and may be fixed values.

Then, the base station in FIG. 1 or 3 transmits “a symbol group formodulated signal 3” which includes “signals in a data transmission areaof modulated signal 3” which are constituted by data symbols. Then, thebase station in FIG. 1 or 3 transmits “a symbol group for modulatedsignal 4” which includes “signals in a data transmission area ofmodulated signal 4” which are constituted by data symbols.

Supplementary Note

As a matter of course, the present disclosure may be carried out bycombining a plurality of the exemplary embodiments and other contentsdescribed herein.

Moreover, each exemplary embodiment and the other contents are onlyexamples. For example, while a “modulating method, an error correctioncoding method (an error correction code, a code length, a coding rateand the like to be used), control information and the like” areexemplified, it is possible to carry out the present disclosure with thesame configuration even when other types of a “modulating method, anerror correction coding method (an error correction code, a code length,a coding rate and the like to be used), control information and thelike” are applied.

As for a modulating method, even when a modulating method other than themodulating methods described herein is used, it is possible to carry outthe exemplary embodiments and the other contents described herein. Forexample, amplitude phase shift keying (APSK), pulse amplitude modulation(PAM), phase shift keying (PSK), and quadrature amplitude modulation(QAM) may be applied, or in each modulating method, uniform mapping ornon-uniform mapping may be performed. APSK includes 16APSK, 64APSK,128APSK, 256APSK, 1024APSK, and 4096APSK, for example. PAM includes4PAM, 8PAM, 16PAM, 64PAM, 128PAM, 256PAM, 1024PAM, and 4096PAM, forexample. PSK includes BPSK, QPSK, 8PSK, 16PSK, 64PSK, 128PSK, 256PSK,1024PSK, and 4096PSK, for example. QAM includes 4QAM, 8QAM, 16QAM,64QAM, 128QAM, 256QAM, 1024QAM, and 4096QAM, for example.

A method for arranging signal points, such as 2 signal points, 4 signalpoints, 8 signal points, 16 signal points, 64 signal points, 128 signalpoints, 256 signal points, and 1024 signal points on an I-Q plane (amodulating method having 2 signal points, 4 signal points, 8 signalpoints, 16 signal points, 64 signal points, 128 signal points, 256signal points, and 1024 signal points, for instance) is not limited to asignal point arranging method according to the modulating methodsdescribed herein.

The “base station” described herein may be a broadcast station, a basestation, an access point, a terminal, or a mobile phone, for example.Then, the “terminal” described herein may be a television, a radio, aterminal, a personal computer, a mobile phone, an access point, or abase station, for instance. The “base station” and the “terminal” in thepresent disclosure may be devices having a communication function, andsuch devices may be configured to be connected with devices for runningapplications such as a television, a radio, a personal computer, and amobile phone, via a certain interface. Furthermore, in the presentembodiment, symbols other than data symbols, such as, for example, apilot symbol and a symbol for control information may be arranged in anymanner in frames.

Then, any names may be given to a pilot symbol and a symbol for controlinformation, and such symbols may be, for example, known symbolsmodulated using PSK modulation in a transmitting device or a receivingdevice. Alternatively, the receiving device may be able to learn asymbol transmitted by the transmitting device by establishingsynchronization. The receiving device performs, using the symbol,frequency synchronization, time synchronization, channel estimation ofeach modulated signal (estimation of channel state information (CSI)),and signal detection, for instance. Note that a pilot symbol may bereferred to as a preamble, a unique word, a postamble, or a referencesymbol, for instance.

Moreover, the control information symbol is a symbol for transmittinginformation that is used for realizing communication other thancommunication for data (data of an application, for instance) and thatis to be transmitted to a communicating party (for example, a modulatingmethod used for communication, an error correction coding method, acoding rate of the error correction coding method, setting informationin an upper layer, and the like).

Note that the present disclosure is not limited to each exemplaryembodiment, and can be carried out with various modifications. Forexample, the case where the present disclosure is performed as acommunication device is described in each exemplary embodiment. However,the present disclosure is not limited to this case, and thiscommunication method can also be used as software.

Note that a program for executing the above-described communicationmethod may be stored in a ROM (Read Only Memory) in advance, and a CPU(Central Processing Unit) may be caused to operate this program.

Moreover, the program for executing the above-described communicationmethod may be stored in a computer-readable storage medium, the programstored in the recording medium may be recorded in a RAM (Random AccessMemory) of a computer, and the computer may be caused to operateaccording to this program.

Then, the configurations of the above-described exemplary embodiments,for instance, may be each realized as an LSI (Large Scale Integration)which is typically an integrated circuit having an input terminal and anoutput terminal. The configurations may be separately formed as onechip, or all or at least one of the configurations of the exemplaryembodiments may be formed as one chip. The LSI is described here, butthe integrated circuit may also be referred to as an IC (IntegratedCircuit), a system LSI, a super LSI, or an ultra LSI, depending on adegree of integration. Moreover, a circuit integration technique is notlimited to the LSI, and may be realized by a dedicated circuit or ageneral purpose processor. After manufacturing of the LSI, aprogrammable FPGA (Field Programmable Gate Array) or a reconfigurableprocessor which is reconfigurable in connection or settings of circuitcells inside the LSI may be used. Further, when development of asemiconductor technology or another derived technology provides acircuit integration technology which replaces the LSI, as a matter ofcourse, functional blocks may be integrated by using this technology.Application of biotechnology, for instance, is one such possibility.

Embodiment 3

The present embodiment describes a multicast communication method whenbeamforming different from the beamforming in Embodiments 1 and 2 isapplied.

The configuration of the base station is as described with reference toFIGS. 1 to 3 in Embodiment 1, and thus a description of portions whichoperate in the same manner as those in Embodiment 1 is omitted. Also theconfiguration of a terminal which communicates with a base station is asdescribed with reference to FIGS. 4 to 6 in Embodiment 1, and thus adescription of portions which operate in the same manner as those inEmbodiment 1 is omitted.

The following describes an example of operation of a base station and aterminal in the present embodiment.

FIG. 22 illustrates the case where the base station transmits atransmission stream for multicasting to one terminal.

In FIG. 22, base station 700 transmits transmission beam 2201-1 for“stream 1-1 (a first beam for stream 1) (for multicasting)” from anantenna for transmission to terminal 2202-1, and terminal 2202-1performs directivity control to generate receiving directivity 2203-1,and receives transmission beam 2201-1 for “stream 1-1”.

FIG. 23 is for describing a “procedure for performing communicationbetween a base station and a terminal” to achieve the state ofcommunication between the base station and the terminal as illustratedin FIG. 22.

[23-1] First, the terminal transmits a “request to transmit stream 1 bymulticasting” to a base station.

[23-2] Upon receiving [23-1], the base station becomes aware that thebase station “is not transmitting stream 1 by multicasting”. Then, thebase station transmits, to the terminal, a training symbol fortransmission directivity control, and a training symbol for receivingdirectivity control, in order to transmit stream 1 by multicasting.

[23-3] The terminal receives the training symbol for transmissiondirectivity control and the training symbol for receiving directivitycontrol transmitted by the base station, and transmits feedbackinformation to the base station in order that the base station performstransmission directivity control and the terminal performs receivingdirectivity control. [23-4] The base station determines a method fortransmission directivity control (determines, for instance, a weightingfactor to be used for directivity control), based on the feedbackinformation transmitted by the terminal, performs transmissiondirectivity control, and transmits data symbols for stream 1.

[23-5] The terminal determines a receiving directivity control method(determines, for instance, a weighting factor to be used for directivitycontrol), and starts receiving the data symbols for stream 1 transmittedby the base station.

Note that the “procedure for a base station and a terminal tocommunicate” in FIG. 23 is an example, and the order of transmittinginformation items is not limited to the order in FIG. 23, andcommunication between the base station and the terminal can be similarlyestablished even if the order of transmitting information items haschanged. FIG. 23 illustrates, as an example, the case in which theterminal performs receiving directivity control, yet the terminal maynot perform receiving directivity control. In such a case, the basestation may not transmit a training symbol for receiving directivitycontrol and the terminal does not determine a receiving directivitycontrol method, in FIG. 23.

When the base station performs transmission directivity control, if thebase station has a configuration in FIG. 1, for example, multiplicationcoefficients for multipliers 204-1, 204-2, 204-3, and 204-4 in FIG. 2are determined, whereas if the base station has a configuration in FIG.3, weighting factors for weighting synthesizer 301 are determined, forexample. Note that the number of streams to be transmitted is “1” inFIG. 22, yet the present disclosure is not limited to this.

When the terminal performs receiving directivity control, if theterminal has a configuration in FIG. 4, for example, multiplicationcoefficients for multipliers 503-1, 503-2, 503-3, and 503-4 in FIG. 5are determined, whereas when the terminal has the configuration in FIG.6, multiplication coefficients for multipliers 603-1, 603-2, . . . , and603-L, for example, are determined.

FIG. 24 is a diagram illustrating examples of symbols which the basestation transmits and symbols which a terminal transmits along atime-axis, when the base station in FIG. 23 transmits a symbol fortransmission directivity control, a symbol for receiving directivitycontrol, and data symbols. In FIG. 24, (a) is a diagram illustratingexamples of symbols which the base station transmits, along thetime-axis, and (b) is a diagram illustrating examples of symbols whichthe terminal transmits along the time-axis, while the horizontal axisindicates time in both of (a) and (b).

When the base station and the terminal communicate with each other asillustrated in FIG. 23, first, the base station transmits “base stationtransmission directivity control training symbol” 2401 as illustrated inFIG. 24. For example, “base station transmission directivity controltraining symbol” 2401 includes a control information symbol and a knownPSK symbol.

Then, the terminal receives “base station transmission directivitycontrol training symbol” 2401 transmitted by the base station, andtransmits, as feedback information symbol 2402, information on anantenna to be used by the base station for transmission and informationon multiplication coefficients (or weighting factors) to be used fordirectivity control, for example.

The base station receives “feedback information symbol” 2402 transmittedby the terminal, determines an antenna to be used for transmission fromfeedback information symbol 2402, and determines a coefficient to beused for transmission directivity control from feedback informationsymbol 2402. After that, the base station transmits “terminal receivingdirectivity control training symbol” 2403. For example, “terminalreceiving directivity control training symbol” 2403 includes a controlinformation symbol and a known PSK symbol.

Then, the terminal receives “terminal receiving directivity controltraining symbol” 2403 transmitted by the base station, and determines anantenna which the terminal is to use for receiving and a multiplicationcoefficient which the terminal is to use for receiving directivitycontrol, for example. Then, the terminal transmits feedback informationsymbol 2404, notifying that preparation for receiving data symbols iscompleted.

Then, the base station receives “feedback information symbol” 2404transmitted by the terminal, and outputs data symbols 2405 based onfeedback information symbol 2404.

Note that communication between the base station and the terminal inFIG. 24 is an example, and the order of transmitting symbols and theorder in which the base station and the terminal transmit symbols arenot limited to those illustrated therein. “Base station transmissiondirectivity control training symbol” 2401, “feedback information symbol”2402, “terminal receiving directivity control training symbol” 2403,“feedback information symbol” 2404, and “data symbols” 2405 may eachinclude: a preamble for signal detection, time synchronization,frequency synchronization, frequency offset estimation, and channelestimation, a reference symbol, a pilot symbol, and a symbol fortransmitting control information, for instance.

FIG. 25 illustrates examples of symbols which the base station transmitwhen the base station transmits data symbols for stream 1 aftercommunication between the base station and the terminal in FIG. 23 iscompleted, while the horizontal axis indicates time.

In FIG. 25, the base station transmits a first data symbol fortransmission beam 1 for stream 1 as “stream 1-1 data symbol (1) (formulticasting)” 2501-1-1. After that, section 2502-1 in which datasymbols can be transmitted is arranged.

After that, the base station transmits a second data symbol fortransmission beam 1 for stream 1 (for multicasting) as “stream 1-1 datasymbol (2) (for multicasting)” 2501-1-2. After that, section 2502-2 inwhich data symbols can be transmitted is arranged.

After that, the base station transmits a third data symbol fortransmission beam 1 for stream 1 (for multicasting) as “stream 1-1 datasymbol (3) (for multicasting)” 2501-1-3.

Accordingly, the base station transmits data symbols for “stream (formulticasting) 1-1” 2201-1 illustrated in FIG. 22. Note that in FIG. 25,“stream 1-1 data symbol (1) (for multicasting)” 2501-1-1, “stream 1-1data symbol (2) (for multicasting)” 2501-1-2, “data symbol 1-1 datasymbol (3) (for multicasting)” 2501-1-3, and so on may each include,other than a data symbol, a preamble for signal detection, timesynchronization, frequency synchronization, frequency offset estimation,and channel estimation, a reference symbol, a pilot symbol, and a symbolfor transmitting control information, for instance.

Note that in FIG. 25, section 2502-1 in which data symbols can betransmitted includes unicast transmitting section 2503-1, and section2502-2 in which data symbols can be transmitted includes unicasttransmitting section 2503-2.

In FIG. 25, a frame includes unicast transmitting sections 2503-1 and2503-2. For example, in FIG. 25, the base station may transmit symbolsfor multicasting in a section within section 2502-1 in which datasymbols can be transmitted and other than unicast transmitting section2503-1, and a section within section 2502-2 in which data symbols can betransmitted and other than unicast transmitting section 2503-2. Thispoint will be described later using an example.

Thus, including a unicast transmitting section in a frame is a usefulfeature for stably operating a wireless communication system. This pointwill be later described using an example. Note that the unicasttransmitting sections may not be in the temporal positions asillustrated in FIG. 25, and may be arranged in any temporal positions.Note that in the unicast transmitting sections, the base station maytransmit symbols or the terminal may transmit symbols.

Furthermore, a configuration may be adopted in which the base stationcan directly set a unicast transmitting section, or as another method,the base station may set the maximum transmission-data transmissionspeed for transmitting symbols for multicasting.

For example, when the transmission speed at which the base station cantransmit data is 2 Gbps (bps: bits per second) and the maximumtransmission speed at which the base station can transmit data that canbe assigned to transmit symbols for multicasting is 1.5 Gbps, a unicasttransmitting section corresponding to 500 Mbps can be set.

Accordingly, a configuration may be adopted in which the base stationcan indirectly set a unicast transmitting section. Note that anotherspecific example will be described later.

Note that in accordance with the state in FIG. 22, FIG. 25 illustrates aframe configuration in which “stream 1-1 data symbol (1) (formulticasting)” 2501-1-1, “stream 1-1 data symbol (2) (for multicasting)”2501-1-2, and “data symbol 1-1 data symbol (3) (for multicasting)”2501-1-3 are present, yet the present disclosure is not limited to sucha frame configuration. For example, a data symbol for a stream formulticasting other than stream 1 (stream 1-1) may be present, a datasymbol for stream 1-2 which is a second transmission beam for stream 1,and a data symbol for stream 1-3 which is a third transmission beam forstream 1 may be present. This point will be described later.

FIG. 26 illustrates a state when a terminal is newly added to the statein FIG. 22 in which the base station transmits transmission streams formulticasting to one terminal, and elements which operate in the samemanner as those in FIG. 22 are assigned the same reference numerals.

In FIG. 26, the terminal newly added is 2202-2. Terminal 2202-2generates receiving directivity 2203-2 by performing directivitycontrol, and receives transmission beam 2201-1 for “stream 1-1 (formulticasting)”.

The following describes FIG. 26.

In the following description, in FIG. 26, terminal 2202-2 newlyparticipates in the multicast communication in a state where basestation 700 and terminal 2202-1 are performing multicast communication.Thus, as illustrated in FIG. 27, the base station transmits “terminalreceiving directivity control training symbol” 2701 and “data symbol”2702, and does not transmit “base station transmission training symbol”illustrated in FIG. 24. Note that in FIG. 27, the horizontal axisindicates time.

FIG. 28 illustrates an example of operation performed to achieve a statein which the base station transmits transmission beams for multicastingto two terminals as illustrated in FIG. 26.

[28-1] Terminal 2202-2 transmits a “request to transmit stream 1 bymulticasting” to the base station. Note that the “request to transmitstream 1 by multicasting” is transmitted in a unicast transmittingsection in FIG. 25.

[28-2] Upon receiving [28-1], the base station notifies terminal 2202-2that “the base station is transmitting stream 1 for multicasting”. Notethat the base station transmits a notification indicating that “the basestation is transmitting stream 1 for multicasting” in a unicasttransmitting section in FIG. 25.

[28-3] Upon receiving [28-2], terminal 2202-2 performs receivingdirectivity control, in order to start receiving stream 1 formulticasting. Then, terminal 2202-2 performs receiving directivitycontrol, and notifies the base station that “terminal 2202-2 hassuccessfully received stream 1 for multicasting”.

[28-4] Upon receiving [28-3], the base station becomes aware that theterminal has successfully received “stream 1 for multicasting”.

[28-5] Terminal 2202-2 performs receiving directivity control, andstarts receiving “stream 1 for multicasting”.

FIG. 29 illustrates that a terminal is newly added to a state in FIG. 22in which the base station is transmitting a transmission stream formulticasting to one terminal. Elements which operate in the same manneras those in FIG. 22 are assigned the same reference numerals.

In FIG. 29, the terminal newly added is 2202-2. At this time, differentpoints from FIG. 26 are that base station 700 newly transmitstransmission beam 2201-2 for “stream 1-2 (second transmission beam forstream 1) (for multicasting)”, and terminal 2202-2 performs directivitycontrol to generate receiving directivity 2203-2, and receivestransmission beam 2201-2 for “stream 1-2 (for multicasting)”.

The following describes control for achieving the state as in FIG. 29.

In the following description, in FIG. 29, terminal 2202-2 newlyparticipates in multicast communication in a state in which base station700 and terminal 2202-1 are performing multicast communication.

FIG. 30 illustrates an example of operation performed in order toachieve a state in which the base station transmits transmission beamsfor multicasting to two terminals, as illustrated in FIG. 29.

[30-1] Terminal 2202-2 transmits a “request to transmit stream 1 bymulticasting” to the base station. Note that the “request to transmitstream 1 by multicasting” is transmitted in a unicast transmittingsection in FIG. 25.

[30-2] Upon receiving [30-1], the base station notifies terminal 2202-2that “the base station is transmitting stream 1 for multicasting”. Notethat the base station transmits a notification indicating that “the basestation is transmitting stream 1 for multicasting” in a unicasttransmitting section in FIG. 25.

[30-3] Upon receiving [30-2], terminal 2202-2 notifies the base stationthat “terminal 2202-2 has not received stream 1 for multicasting”. Notethat terminal 2202-2 transmits the notification indicating that “stream1 for multicasting is not received” in a unicast transmitting section inFIG. 25.

[30-4] Upon receiving [30-3], the base station determines to transmitanother transmission beam (specifically, transmission beam 2201-2 inFIG. 29) for stream 1 for multicasting. Note that here, the base stationdetermines to transmit another transmission beam for stream 1 formulticasting, yet the base station may determine not to transmit anothertransmission beam for stream 1 for multicasting. This point will belater described.

Thus, the base station transmits a training symbol for transmissiondirectivity control and a training symbol for receiving directivitycontrol to terminal 2202-2, in order to transmit stream 1 bymulticasting. Note that the base station transmits a transmission beamfor stream 1-1 in FIG. 29, separately from transmission of thesesymbols. This point will be described later.

[30-5] Terminal 2202-2 receives a training symbol for transmissiondirectivity control and a training symbol for receiving directivitycontrol which the base station has transmitted, and transmits feedbackinformation to the base station in order that the base station performstransmission directivity control and terminal 2202-2 performs receivingdirectivity control.

[30-6] Based on the feedback information transmitted by terminal 2202-2,the base station determines a method for transmission directivitycontrol (determines, for instance, a weighting factor to be used whenperforming directivity control), and transmits a data symbol for stream1 (transmission beam 2201-2 for stream 1-2 in FIG. 29).

[30-7] Terminal 2202-2 determines a receiving directivity control method(determines, for instance, a weighting factor to be used when performingdirectivity control), and starts receiving data symbols for stream 1(transmission beam 2201-2 for stream 1-2 in FIG. 29) which the basestation has transmitted.

Note that the “procedure for a base station and a terminal tocommunicate” in FIG. 30 is an example, and the order of transmittinginformation items is not limited to the order in FIG. 30. Thus,communication between the base station and the terminal can be similarlyestablished even if the order of transmitting information items haschanged.

FIG. 30 illustrates an example in which the terminal performs receivingdirectivity control, yet the terminal may not perform receivingdirectivity control. In such a case, the base station may not transmit atraining symbol for receiving directivity control, and the terminal maynot determine a receiving directivity control method, in FIG. 30.

When the base station performs transmission directivity control, if thebase station has a configuration in FIG. 1, for example, multiplicationcoefficients for multipliers 204-1, 204-2, 204-3, and 204-4 in FIG. 2are determined, whereas if the base station has a configuration in FIG.3, weighting factors for weighting synthesizer 301 are determined, forexample. Note that the number of streams to be transmitted is “2” in thecase of FIG. 29, yet the present disclosure is not limited to this.

Then, when terminals 2202-1 and 2202-2 perform receiving directivitycontrol, if the terminals have a configuration in FIG. 4, for example,multiplication coefficients for multiplier 503-1, 503-2, 503-3, and503-4 in FIG. 5 are determined, whereas when the terminals have aconfiguration in FIG. 6, multiplication coefficients for multipliers603-1, 603-2, . . . , and 603-L are determined, for example.

FIG. 31 illustrates examples of symbols transmitted by the base stationwhen the base station transmits data symbols for stream 1 aftercommunication between the base station and the terminal in FIG. 30 iscompleted, while the horizontal axis indicates time.

In FIG. 31, “stream 1-1” in FIG. 29 is present, and thus similarly toFIG. 25, “stream 1-1 data symbol (M) (for multicasting)” 2501-1-M,“stream 1-1 data symbol (M+1) (for multicasting)” 2501-1-M+1, and“stream 1-1 data symbol (M+2) (for multicasting)” 2501-1-M+2 arepresent. Note that “(M), (M+1), (M+2)” are illustrated, and this isbecause stream 1-1 (for multicasting) is already present before stream1-2 (for multicasting) is present. Accordingly, in FIG. 31, M is assumedto be an integer of 2 or greater.

Then, as illustrated in FIG. 31, “stream 1-2 data symbol (1) (formulticasting)” 3101-1, “stream 1-2 data symbol (2) (for multicasting)”3101-2, and “stream 1-2 data symbol (3) (for multicasting)” 3101-3 arepresent in sections other than unicast transmitting sections 2503-1 and2503-2.

The features are as follows as described above.

-   -   “Stream 1-1 data symbol (M) (for multicasting)” 2501-1-M,        “stream 1-1 data symbol (M+1) (for multicasting)” 2501-1-M+1,        “stream 1-1 data symbol (M+2) (for multicasting)” 2501-1-M+2,        “stream 1-2 data symbol (1) (for multicasting)” 3101-1, “stream        1-2 data symbol (2) (for multicasting)” 3101-2, and “stream 1-2        data symbol (3) (for multicasting)” 3101-3 are all data symbols        for transmitting “stream 1”.    -   The terminal can obtain “data of stream 1” by obtaining “data        symbols for stream 1-1”. The terminal can obtain “data of stream        1” by obtaining “data symbols for stream 1-2”.    -   The directivities of transmission beams for “stream 1-1 data        symbol (M) (for multicasting)” 2501-1-M, “stream 1-1 data symbol        (M+1) (for multicasting)” 2501-1-M+1, and “stream 1-1 data        symbol (M+2) (for multicasting)” 2501-1-M+2 are different from        the directivities of transmission beams for “stream 1-2 data        symbol (1) (for multicasting)” 3101-1, “stream 1-2 data symbol        (2) (for multicasting)” 3101-2, and “stream 1-2 data symbol (3)        (for multicasting)” 3101-3. Thus, a set of multiplication        coefficients (or weighting factors) for the transmitting device        of the base station used in order to generate transmission beams        for “stream 1-1 data symbol (M) (for multicasting)” 2501-1-M,        “stream 1-1 data symbol (M+1) (for multicasting)” 2501-1-M+1,        and “stream 1-1 data symbol (M+2) (for multicasting)” 2501-1-M+2        are different from a set of multiplication coefficients (or        weighting factors) for the transmitting device of the base        station used in order to generate transmission beams for “stream        1-2 data symbol (1) (for multicasting)” 3101-1, “stream 1-2 data        symbol (2) (for multicasting)” 3101-2, and “stream 1-2 data        symbol (3) (for multicasting)” 3101-3.

The above allows two terminals to receive multicast streams which thebase station has transmitted. At this time, directivity control isperformed by the transmitting device and the receiving device, and thusan advantageous effect of increasing an area in which streams formulticasting can be received is yielded. Furthermore, streams andtransmission beams are added only when necessary, and thus anadvantageous effect of effectively utilizing frequency, time, and spaceresources for transmitting data.

Note that control as described below may be performed. The details ofthe control are as follows.

FIG. 32 illustrates “examples of symbols which the base stationtransmits when the base station transmits data symbols (for stream 1)after communication between the base station and the terminal in FIG. 30is completed”, which are different from FIG. 31, where the horizontalaxis indicates time. Note that elements which operate in the same manneras in FIGS. 25 and 31 are assigned the same reference numerals in FIG.32.

Different points in FIG. 32 from FIG. 31 are that unicast transmittingsections 2503-1 and 2503-2 are set to longer time periods, and thus thebase station does not further add and transmit symbols for multicasting.

FIG. 33 illustrates an example of operation when new terminal 2202-3transmits a request to the base station to add a transmission beam, inaddition to transmission beams for multicasting transmitted by the basestation to two terminals (terminals 2202-1 and 2202-2), as illustratedin FIG. 29. Note that FIG. 32 illustrates a frame of a modulated signalwhich the base station transmits.

[33-1] Terminal 2202-3 transmits to the base station a “request totransmit stream 1 by multicasting”. Note that terminal 2202-3 transmitsthe “request to transmit stream 1 by multicasting” in a unicasttransmitting section in FIG. 32

[33-2] Upon receiving [33-1], the base station notifies terminal 2202-3that “the base station is transmitting stream 1 for multicasting”. Notethat the base station transmits the “notification indicating that thebase station is transmitting stream 1 for multicasting” in a unicasttransmitting section in FIG. 32.

[33-3] Upon receiving [33-2], terminal 2202-3 notifies the base stationthat “terminal 2202-3 has not received stream 1 for multicasting”. Notethat terminal 2202-3 transmits the “notification indicating that stream1 for multicasting has not been received” in a unicast transmittingsection in FIG. 32.

[33-4] Upon receiving [33-3], the base station determines whether atransmission beam other than the transmission beam for stream 1-1 andthe transmission beam for stream 1-2 can be transmitted as atransmission beam for stream 1 for multicasting. At this time, takinginto consideration that the frame is as illustrated in FIG. 32, the basestation determines not to transmit another transmission beam for stream1 for multicasting. Accordingly, the base station notifies terminal2202-3 that “the base station is not to transmit another transmissionbeam for stream 1 for multicasting”. Note that the base stationtransmits the “notification indicating that the base station is not totransmit another transmission beam for stream 1 for multicasting” in aunicast transmitting section in FIG. 32.

[33-5] Terminal 2202-3 receives the “notification indicating that thebase station is not to transmit another transmission beam for stream 1for multicasting”.

Note that the “procedure for a base station and a terminal tocommunicate” in FIG. 33 is an example, and the order of transmittinginformation items is not limited to the order in FIG. 33, so thatcommunication between the base station and the terminal can be similarlyestablished even if the order of transmitting items has changed. In thismanner, if there are insufficient communication resources for multicasttransmission, a multicast transmission beam may not be added.

FIG. 34 illustrates an example of operation when new terminal 2202-3transmits a request to the base station to add a transmission beam foranother stream for multicasting (stream 2), in addition to transmissionbeams for multicasting transmitted by the base station to two terminals(terminals 2202-1 and 2202-2), illustrated in FIG. 29. Note that a frameof a modulated signal transmitted by the base station is in the state asillustrated in FIG. 31.

[34-1] Terminal 2202-3 transmits to the base station a “request totransmit stream 2 by multicasting”. Note that terminal 2202-3 transmitsthe “request to transmit stream 2 by multicasting” in unicasttransmitting section 2503 in FIG. 31.

[34-2] Upon receiving [34-1], the base station notifies terminal 2202-3that “the base station is not transmitting stream 2 for multicasting”.In addition, the base station determines “whether the base station canadd and transmit a transmission beam for stream 2 for multicasting”. Atthis time, taking into consideration that the frame is in the state asillustrated in FIG. 31, the base station notifies terminal 2202-3 that“the base station is able to transmit a transmission beam for stream 2for multicasting”. Note that the base station transmits the“notification indicating that the base station is not transmittingstream 2 for multicasting” and the “notification indicating that thebase station is able to transmit a transmission beam for stream 2 formulticasting” in unicast transmitting section 2503 in FIG. 31.

[34-3] Upon receiving [34-2], terminal 2202-3 notifies the base stationthat “terminal 2203-3 is ready to receive stream 2 for multicasting”.Note that terminal 2202-3 transmits the notification indicating that“terminal 2202-3 is ready to receive stream 2 for multicasting” inunicast transmitting section 2503 in FIG. 31.

[34-4] Upon receiving [34-3], the base station determines to transmit atransmission beam for stream 2 for multicasting. Then, the base stationtransmits a training symbol for transmission directivity control and atraining symbol for receiving directivity control, in order to transmitstream 2 to terminal 2202-3 by multicasting. Note that the base stationtransmits transmission beams for streams 1-1 and 1-2, as illustrated inFIG. 31, separately from transmission of the above symbols. This pointwill be described later.

[34-5] Terminal 2202-3 receives the training symbol for transmissiondirectivity control and the training symbol for receiving directivitycontrol which the base station has transmitted, and transmits feedbackinformation to the base station in order that the base station performstransmission directivity control and terminal 2202-3 performs receivingdirectivity control.

[34-6] Based on the feedback information transmitted by terminal 2202-3,the base station determines a method for transmission directivitycontrol (determines a weighting factor used for directivity control, forinstance), and transmits data symbols for stream 2.

[34-7] Terminal 2202-3 determines a receiving directivity control method(determines a weighting factor used for directivity control, forinstance), and starts receiving the data symbols for stream 2 which thebase station has transmitted.

Note that the “procedure for a base station and a terminal tocommunicate” in FIG. 34 is an example, and the order of transmittinginformation items is not limited to the order in FIG. 34, andcommunication between the base station and the terminal can be similarlyestablished even if the order of transmitting information items haschanged. FIG. 34 illustrates an example in which the terminal performsreceiving directivity control, yet the terminal may not performreceiving directivity control. In such a case, the base station may nottransmit a training symbol for receiving directivity control, and theterminal does not determine a receiving directivity control method, inFIG. 34.

When the base station performs transmission directivity control, forexample, multiplication coefficients for multipliers 204-1, 204-2,204-3, and 204-4 in FIG. 2 are determined if the base station has aconfiguration in FIG. 1.

Then, when terminals 2202-1, 2202-2, and 2202-3 perform receivingdirectivity control, if the terminals have a configuration in FIG. 4,multiplication coefficients for multipliers 503-1, 503-2, 503-3, and503-4 in FIG. 5 are determined, for example, whereas if the terminalshave a configuration in FIG. 6, multiplication coefficients formultipliers 603-1, 603-2, . . . , and 603-L are determined, for example.

FIG. 35 illustrates examples of symbols which the base station transmitswhen the base station transmits data symbols for stream 1 and stream 2after communication between the base station and a terminal in FIG. 34is completed, where the horizontal axis indicates time.

In FIG. 35, “stream 1-1” and “stream 1-2” illustrated in FIG. 31 arepresent, and thus “stream 1-1 data symbol (M) (for multicasting)”2501-1-M, “stream 1-1 data symbol (M+1) (for multicasting)” 2501-1-M+1,and “stream 1-1 data symbol (M+2) (for multicasting)” 2501-1-M+2 arepresent. In addition, “stream 1-2 data symbol (N) (for multicasting)”3101-N, “stream 1-2 data symbol (N+1) (for multicasting)” 3101-N+1, and“stream 1-2 data symbol (N+2) (for multicasting)” 3101-N+2 are present.Note that N and M are integers of 2 or greater.

As illustrated in FIG. 35, in sections other than unicast transmittingsections 2503-1 and 2503-2, “stream 2-1 data symbol (1) (formulticasting)” 3501-1, “stream 2-1 data symbol (2) (for multicasting)”3501-2, and “stream 2-1 data symbol (3) (for multicasting)” 3501-3 arepresent.

As described above, the features achieved at this time are as follows.

-   -   “Stream 1-1 data symbol (M) (for multicasting)” 2501-1-M,        “stream 1-1 data symbol (M+1) (for multicasting)” 2501-1-M+1,        “stream 1-1 data symbol (M+2) (for multicasting)” 2501-1-M+2,        “stream 1-2 data symbol (N) (for multicasting)” 3101-N, “stream        1-2 data symbol (N+1) (for multicasting)” 3101-N+1, and “stream        1-2 data symbol (N+2) (for multicasting)” 3101-N+2 are all data        symbols for transmitting “stream 1”.    -   A terminal obtains “data of stream 1” by obtaining “data symbols        for stream 1-1”. Further, the terminal obtains “data of stream        1” by obtaining “data symbols for stream 1-2”.    -   The directivities of transmission beams for “stream 1-1 data        symbol (M) (for multicasting)” 2501-1-M, “stream 1-1 data symbol        (M+1) (for multicasting)” 2501-1-M+1, and “stream 1-1 data        symbol (M+2) (for multicasting)” 2501-1-M+2 are different from        the directivities of transmission beams for “stream 1-2 data        symbol (1) (for multicasting)” 3101-1, “stream 1-2 data symbol        (2) (for multicasting)” 3101-2, and “stream 1-2 data symbol (3)        (for multicasting)” 3101-3.

Thus, a set of multiplication coefficients (or weighting factors) forthe transmitting device of the base station used in order to generatetransmission beams for “stream 1-1 data symbol (M) (for multicasting)”2501-1-M, “stream 1-1 data symbol (M+1) (for multicasting)” 2501-1-M+1,and “stream 1-1 data symbol (M+2) (for multicasting)” 2501-1-M+2 isdifferent from a set of multiplication coefficients (or weightingfactors) for the transmitting device of the base station used in orderto generate transmission beams for “stream 1-2 data symbol (1) (formulticasting)” 3101-1, “stream 1-2 data symbol (2) (for multicasting)”3101-2, and “stream 1-2 data symbol (3) (for multicasting)” 3101-3.

-   -   “Stream 2-1 data symbol (1) (for multicasting)” 3501-1, “stream        2-1 data symbol (2) (for multicasting)” 3501-2, and “stream 2-1        data symbol (3) (for multicasting)” 3501-3 are data symbols for        transmitting “stream 2”.    -   A terminal obtains data of “stream 2” by obtaining “data symbols        for stream 2-1”. The above allows the terminal to receive a        plurality of multicast streams (streams 1 and 2) transmitted by        the base station. At this time, directivity control is performed        by the transmitting device and the receiving device, and thus an        advantageous effect of increasing an area in which streams for        multicasting can be received is yielded. Furthermore, streams        and transmission beams are added only when necessary, and thus        an advantageous effect of effectively utilizing frequency, time,        and space resources for transmitting data.

Note that control as described below may be performed. The details ofthe control are as follows.

FIG. 32 illustrates “examples of symbols which the base stationtransmits when the base station transmits data symbols (for stream 1)”,which is different from FIG. 35, where the horizontal axis indicatestime. Note that elements which operate in the same manner as those inFIGS. 25 and 31 are assigned the same reference numerals in FIG. 32.

Different points in FIG. 32 from FIG. 35 are that unicast transmittingsections 2503-1 and 2503-2 are set to longer time periods, and thus thebase station does not add and transmit any more symbols formulticasting, that is, for example, symbols for a new stream.

FIG. 36 illustrates an example of operation when new terminal 2202-3transmits a request to the base station to add a transmission beam foranother stream for multicasting (stream 2), in addition to transmissionbeams for multicasting transmitted by the base station to two terminals(terminals 2202-1 and 2202-2), as illustrated in FIG. 29. Note that FIG.32 illustrates a frame of a modulated signal which the base stationtransmits.

[36-1] Terminal 2202-3 transmits to the base station a “request totransmit stream 2 by multicasting”. Note that terminal 2202-3 transmitsthe “request to transmit stream 2 by multicasting” in a unicasttransmitting section in FIG. 32

[36-2] Upon receiving [36-1], the base station notifies terminal 2202-3that “the base station is not transmitting stream 2 for multicasting”.Note that the base station transmits the notification indicating that“the base station is not transmitting stream 2 for multicasting” in aunicast transmitting section in FIG. 32. In addition, the base stationdetermines whether a transmission beam for stream 2 for multicasting canbe transmitted. Taking the frame illustrated in FIG. 32 intoconsideration, the base station determines not to transmit atransmission beam for stream 2 for multicasting. Thus, the base stationnotifies terminal 2202-3 that “the base station is not to transmitstream 2 for multicasting”. Note that the base station transmits the“notification indicating that the base station is not to transmit stream2 for multicasting” in a unicast transmitting section in FIG. 32.

[36-3] Terminal 2202-3 receives the “notification indicating that thebase station is not to transmit stream 2 for multicasting”.

Note that the “procedure for a base station and a terminal tocommunicate” in FIG. 36 is an example, and the order of transmittinginformation items is not limited to the order in FIG. 36. Communicationbetween the base station and the terminal can be similarly establishedeven if the procedure of transmitting items has changed. In this manner,if there are insufficient communication resources for multicasttransmission, a stream and a multicast transmission beam may not beadded.

Note that a supplemental description of a method for setting unicasttransmitting sections 2503-1 and 2503-2 illustrated in, for instance,FIG. 35 is now given.

For example, in FIG. 35, the maximum value of the number of transmissionbeams for multicasting is determined in advance or is set.

In response to requests from the terminals, the base station transmitstransmission beams for multicasting, the number of which is smaller thanor equal to the maximum value. For example, in the case of FIG. 35, thenumber of transmission beams for multicasting is 3. Then, the basestation transmits a plurality of transmission beams for multicasting,and temporal idle time after transmitting the transmission beams is setas a unicast transmitting section.

The unicast transmitting sections may be determined as described above.

Supplementary Note 1

Supplementary Note 1 describes the case where a base station performsunicast communication with a plurality of terminals, or in other words,communicates separately with a plurality of terminals.

At this time, for example, #1 symbol group 901-1 for stream 1, #2 symbolgroup 901-2 for stream 1, and #3 symbol group 901-3 for stream 1 in FIG.9 may be control information for broadcast channels, that is, controlinformation which the base station transmits by broadcasting to aplurality of terminals in order that the base station performs datacommunication with the plurality of terminals. Note that controlinformation is to be used to, for example, establish data communicationbetween the base station and a terminal.

For example, #1 symbol group 901-1 for stream 1, #2 symbol group 901-2for stream 1, and #3 symbol group 901-3 for stream 1 in FIG. 9 may becommon search spaces. Note that a common search space is controlinformation for cell control. Also, a common search space is controlinformation broadcast to a plurality of terminals.

Similarly, for example, #1 symbol group 902-1 for stream 2, #2 symbolgroup 902-2 for stream 2, and #3 symbol group 902-3 for stream 2 in FIG.9 may be control information for broadcast channels, that is, controlinformation which the base station transmits by broadcasting to aplurality of terminals in order that the base station performs datacommunication with the plurality of terminals.

For example, #1 symbol group 902-1 for stream 2, #2 symbol group 902-2for stream 2, and #3 symbol group 902-3 for stream 2 in FIG. 9 may becommon search spaces.

Note that features of #1 symbol group 901-1 for stream 1, #2 symbolgroup 901-2 for stream 1, #3 symbol group 901-3 for stream 1, #1 symbolgroup 902-1 for stream 2, #2 symbol group 902-2 for stream 2, and #3symbol group 902-3 for stream 2 in FIG. 9 are as described in the aboveembodiments.

For example, #1 symbol group 1401-1 for modulated signal 1, #2 symbolgroup 1401-2 for modulated signal 1, and #3 symbol group 1401-3 formodulated signal 1 in FIG. 14 may be control information for broadcastchannels, that is, control information which the base station transmitsby broadcasting to a plurality of terminals in order that the basestation performs data communication with the plurality of terminals.

In addition, for example, #1 symbol group 1401-1 for modulated signal 1,#2 symbol group 1401-2 for modulated signal 1, and #3 symbol group1401-3 for modulated signal 1 in FIG. 14 may be common search spaces.

For example, #1 symbol group 1402-1 for modulated signal 2, #2 symbolgroup 1402-2 for modulated signal 2, and #3 symbol group 1402-3 formodulated signal 2 in FIG. 14 may be control information for broadcastchannels, that is, control information which the base station transmitsby broadcasting to a plurality of terminals in order that the basestation performs data communication with the plurality of terminals.

For example, #1 symbol group 1402-1 for modulated signal 2, #2 symbolgroup 1402-2 for modulated signal 2, and #3 symbol group 1402-3 formodulated signal 2 in FIG. 14 may be common search spaces.

Note that #1 symbol group 1401-1 for modulated signal 1, #2 symbol group1401-2 for modulated signal 1, and #3 symbol group 1401-3 for modulatedsignal 1 in FIG. 14 are as described in the above embodiments, and #1symbol group 1402-1 for modulated signal 2, #2 symbol group 1402-2 formodulated signal 2, and #3 symbol group 1402-3 for modulated signal 2 inFIG. 14 are as described in the above embodiments.

For example, stream 1-1 data symbol (1) 2501-1-1, stream 1-1 data symbol(2) 2501-1-2, and stream 1-1 data symbol (3) 2501-1-3 in FIG. 25 may becontrol information for broadcast channels, that is, control informationwhich the base station transmits by broadcasting to a plurality ofterminals in order that the base station performs data communicationwith the plurality of terminals.

Stream 1-1 data symbol (1) 2501-1-1, stream 1-1 data symbol (2)2501-1-2, and stream 1-1 data symbol (3) 2501-1-3 in FIG. 25 may becommon search spaces.

Note that stream 1-1 data symbol (1) 2501-1-1, stream 1-1 data symbol(2) 2501-1-2, and stream 1-1 data symbol (3) 2501-1-3 in FIG. 25 are asdescribed in the above embodiments.

For example, stream 1-1 data symbol (M) 2501-1-M, stream 1-1 data symbol(M+1) 2501-1-M+1, stream 1-1 data symbol (M+2) 2501-1-M+2, stream 1-2data symbol (1) 3101-1, stream 1-2 data symbol (2) 3101-2, and stream1-2 data symbol (3) 3101-3 in FIGS. 31 and 32 may be control informationfor broadcast channels, that is, control information which the basestation transmits by broadcasting to a plurality of terminals in orderthat the base station performs data communication with the plurality ofterminals.

Further, stream 1-1 data symbol (M) 2501-1-M, stream 1-1 data symbol(M+1) 2501-1-M+1, stream 1-1 data symbol (M+2) 2501-1-M+2, stream 1-2data symbol (1) 3101-1, stream 1-2 data symbol (2) 3101-2, and stream1-2 data symbol (3) 3101-3 in FIGS. 31 and 32 may be common searchspaces.

Note that stream 1-1 data symbol (M) 2501-1_M, stream 1-1 data symbol(M+1) 2501-1_M+1, stream 1-1 data symbol (M+2) 2501-1_M+2, stream 1-2data symbol (1) 3101_1, stream 1-2 data symbol (2) 3101_2, and stream1-2 data symbol (3) 3101_3 in FIGS. 31 and 32 are as described in theabove embodiments.

For example, in FIG. 35, stream 1-1 data symbol (M) 2501-1-M, stream 1-1data symbol (M+1) 2501-1-M+1, stream 1-1 data symbol (M+2) 2501-1-M+2,stream 1-2 data symbol (N) 3101-N, stream 1-2 data symbol (N+1)3101-N+1, and stream 1-2 data symbol (N+2) 3101-N+2 may be controlinformation for broadcast channels, that is, control information whichthe base station transmits by broadcasting to a plurality of terminalsin order that the base station performs data communication with theplurality of terminals.

Further, in FIG. 35, stream 1-1 data symbol (M) 2501-1-M, stream 1-1data symbol (M+1) 2501-1-M+1, stream 1-1 data symbol (M+2) 2501-1-M+2,stream 1-2 data symbol (N) 3101-N, stream 1-2 data symbol (N+1)3101-N+1, and stream 1-2 data symbol (N+2) 3101-N+2 may be common searchspaces.

For example, stream 2-1 data symbol (1) 3501-1, stream 2-1 data symbol(2) 3501-2, and stream 2-1 data symbol (3) 3501-3 in FIG. 35 may becontrol information for broadcast channels, that is, control informationwhich the base station transmits by broadcasting to a plurality ofterminals in order that the base station performs data communicationwith the plurality of terminals.

Further, stream 2-1 data symbol (1) 3501-1, stream 2-1 data symbol (2)3501-2, and stream 2-1 data symbol (3) 3501-3 in FIG. 35 may be commonsearch spaces.

Note that in FIG. 35, stream 1-1 data symbol (M) 2501-1-M, stream 1-1data symbol (M+1) 2501-1-M+1, stream 1-1 data symbol (M+2) 2501-1-M+2,stream 1-2 data symbol (N) 3101-N, stream 1-2 data symbol (N+1)3101-N+1, and stream 1-2 data symbol (N+2) 3101-N+2 are as described inthe above embodiments, and stream 2-1 data symbol (1) 3501-1, stream 2-1data symbol (2) 3501-2, and stream 2-1 data symbol (3) 3501-3 in FIG. 35are as described in the above embodiments.

In FIGS. 9, 14, 25, 31, 32, and 35, when data symbols are transmitted, asingle carrier transmission method may be used, or a multi-carriertransmission method such as OFDM may be used. In addition, temporalpositions of data symbols are not limited to the positions in FIGS. 9,14, 25, 31, 32, and 35.

Although a description is given with reference to FIGS. 25, 31, 32, and35, assuming that the horizontal axis indicates time, similar datatransmission can be carried out even if the horizontal axis indicatesfrequency (carrier). Note that when the horizontal axis indicatesfrequency (carrier), the base station transmits data symbols using oneor more carriers or subcarriers.

Supplementary Note 2

Supplementary Note 2 describes the case where the base station performsunicast communication with a plurality of terminals, or in other words,communicates separately with a plurality of terminals.

At this time, for example, #1 symbol group 901-1 for stream 1, #2 symbolgroup 901-2 for stream 1, #3 symbol group 901-3 for stream 1, #1 symbolgroup 902-1 for stream 2, and #2 symbol group 902-2 for stream 2, and #3symbol group 902-3 for stream 2 in FIG. 9 may be data addressed to thebase station or data addressed to a terminal among a plurality ofterminals communicating with the base station. At this time, such datamay include control information.

Note that #1 symbol group 901-1 for stream 1, #2 symbol group 901-2 forstream 1, #3 symbol group 901-3 for stream 1, #1 symbol group 902-1 forstream 2, #2 symbol group 902-2 for stream 2, and #3 symbol group 902-3for stream 2 in FIG. 9 are as described in the above embodiments.

For example, #1 symbol group 1401-1 for modulated signal 1, #2 symbolgroup 1401-2 for modulated signal 1, #3 symbol group 1401-3 formodulated signal 1, #1 symbol group 1401-3 for modulated signal 2, and#2 symbol group 1402-2 for modulated signal 2, and #3 symbol group1402-3 for modulated signal 2 in FIG. 14 may be data addressed to thebase station or data addressed to a terminal among a plurality ofterminals communicating with the base station. At this time, such datamay include control information.

Note that #1 symbol group 1401-1 for modulated signal 1, #2 symbol group1401-2 for modulated signal 1, #3 symbol group 1401-3 for modulatedsignal 1, #1 symbol group 1401-3 for modulated signal 2, and #2 symbolgroup 1402-2 for modulated signal 2, and #3 symbol group 1402-3 formodulated signal 2 in FIG. 14 are as described in the above embodiments.

For example, stream 1-1 data symbol (1) 2501-1-1, stream 1-1 data symbol(2) 2501-1-2, and stream 1-1 data symbol (3) 2501-1-3 in FIG. 25 may bedata addressed to the base station or data addressed to a terminal amonga plurality of terminals communicating with the base station. At thistime, such data may include control information.

Note that stream 1-1 data symbol (1) 2501-1-1, stream 1-1 data symbol(2) 2501-1-2, and stream 1-1 data symbol (3) 2501-1-3 in FIG. 25 are asdescribed in the above embodiments.

For example, stream 1-1 data symbol (M) 2501-1-M, stream 1-1 data symbol(M+1) 2501-1-M+1, stream 1-1 data symbol (M+2) 2501-1-M+2, stream 1-2data symbol (1) 3101-1, stream 1-2 data symbol (2) 3101-2, and stream1-2 data symbol (3) 3101-3 in FIGS. 31 and 32 may be data addressed tothe base station or data addressed to a terminal among a plurality ofterminals communicating with the base station. At this time, such datamay include control information.

Note that stream 1-1 data symbol (M) 2501-1-M, stream 1-1 data symbol(M+1) 2501-1-M+1, stream 1-1 data symbol (M+2) 2501-1-M+2, stream 1-2data symbol (1) 3101-1, stream 1-2 data symbol (2) 3101-2, and stream1-2 data symbol (3) 3101-3 in FIGS. 31 and 32 are as described in theabove embodiments.

For example, in FIG. 35, stream 1-1 data symbol (M) 2501-1-M, stream 1-1data symbol (M+1) 2501-1-M+1, stream 1-1 data symbol (M+2) 2501-1-M+2,stream 1-2 data symbol (N) 3101-N, stream 1-2 data symbol (N+1)3101-N+1, and stream 1-2 data symbol (N+2) 3101-N+2 may be dataaddressed to the base station or data addressed to a terminal among aplurality of terminals communicating with the base station. At thistime, such data may include control information.

For example, stream 2-1 data symbol (1) 3501-1, stream 2-1 data symbol(2) 3501-2, and stream 2-1 data symbol (3) 3501-3 in FIG. 35 may be dataaddressed to the base station or data addressed to a terminal among aplurality of terminals communicating with the base station. At thistime, such data may include control information.

Note that in FIG. 35, stream 1-1 data symbol (M) 2501-1-M, stream 1-1data symbol (M+1) 2501-1-M+1, stream 1-1 data symbol (M+2) 2501-1-M+2,and stream 1-2 data symbol (N) 3101-N, stream 1-2 data symbol (N+1)3101-N+1, stream 1-2 data symbol (N+2) 3101-N+2, stream 2-1 data symbol(1) 3501-1, stream 2-1 data symbol (2) 3501-2, and stream 2-1 datasymbol (3) 3501-3 are as described in the above embodiments.

In FIGS. 9, 14, 25, 31, 32, and 35, when data symbols are transmitted, asingle carrier transmission method may be used, or a multi-carriertransmission method such as OFDM may be used. In addition, temporalpositions of data symbols are not limited to the positions in FIGS. 9,14, 25, 31, 32, and 35.

Although a description is given with reference to FIGS. 25, 31, 32, and35, assuming that the horizontal axis indicates time, similar datatransmission can be carried out even if the horizontal axis indicatesfrequency (carrier). Note that when the horizontal axis indicatesfrequency (carrier), the base station transmits data symbols using oneor more carriers or subcarriers.

Supplementary Note 3

In a time period in which the base station transmits #1 symbol group901-1 for stream 1, #2 symbol group 901-2 for stream 1, #3 symbol group901-3 for stream 1, #1 symbol group 902-1 for stream 2, and #2 symbolgroup 902-2 for stream 2, and #3 symbol group 902-3 for stream 2 aretransmitted as shown in the frame configuration in FIG. 9, the basestation may transmit another symbol group using a transmission beamdifferent from “a transmission beam for #1 symbol group 901-1 for stream1, a transmission beam for #2 symbol group 901-2 for stream 1, atransmission beam for #3 symbol group 901-3 for stream 1, a transmissionbeam for #1 symbol group 902-1 for stream 2, a transmission beam for #2symbol group 902-2 for stream 2, and a transmission beam for #3 symbolgroup 902-3 for stream 2”.

The base station in FIG. 3 may generate a transmission beam for theabove “other symbol group” through “signal processing by signalprocessor 102 and signal processing by weighting synthesizer 301” or“signal processing by signal processor 102 or signal processing byweighting synthesizer 301”.

Further, in a time period in which the base station transmits #1 symbolgroup 1401-1 for modulated signal 1, #2 symbol group 1401-2 formodulated signal 1, #3 symbol group 1401-3 for modulated signal 1, #1symbol group 1402-1 for modulated signal 2, #2 symbol group 1402-2 formodulated signal 2, and #3 symbol group 1402-3 for modulated signal 2 asshown in the frame configuration in FIG. 14, the base station maytransmit another symbol group using a transmission beam different from“a transmission beam for #1 symbol group 1401-1 for modulated signal 1,a transmission beam for #2 symbol group 1401-2 for modulated signal 1, atransmission beam for #3 symbol group 1401-3 for modulated signal 1, atransmission beam for #1 symbol group 1402-1 for modulated signal 2, atransmission beam for #2 symbol group 1402-2 for modulated signal 2, anda transmission beam for #3 symbol group 1402-3 for modulated signal 2”.

At this time, the “other symbol group” may be a symbol group whichincludes a data symbol addressed to a certain terminal, may be a symbolgroup which includes a control information symbol group, or may be asymbol group which includes another data symbol for multicasting, asdescribed in other portions of the present disclosure.

The base station in FIG. 3 may generate a transmission beam for theabove “other symbol group” through “signal processing by signalprocessor 102 and signal processing by weighting synthesizer 301” or“signal processing by signal processor 102 or signal processing byweighting synthesizer 301”.

Supplementary Note 4

In time periods in which a base station transmits stream 1-1 data symbol(1) 2501-1-1, stream 1-1 data symbol (2) 2501-1-2, and stream 1-1 datasymbol (3) 2501-1-3 as shown in the frame configuration in FIG. 25, thebase station may transmit another symbol group using a transmission beamdifferent from “transmission beams for transmitting stream 1-1 datasymbol (1) 2501-1-1, stream 1-1 data symbol (2) 2501-1-2, and stream 1-1data symbol (3) 2501-1-3”.

Note that the same also applies to the case where the horizontal axisindicates frequency in FIG. 25, and in time periods in which the basestation transmits stream 1-1 data symbol (1) 2501-1-1, stream 1-1 datasymbol (2) 2501-1-2, and stream 1-1 data symbol (3) 2501-1-3, the basestation may transmit another symbol group using a transmission beamdifferent from “transmission beams for transmitting stream 1-1 datasymbol (1) 2501-1-1, stream 1-1 data symbol (2) 2501-1-2, and stream 1-1data symbol (3) 2501-1-3.

In time periods in which the base station transmits stream 1-1 datasymbol (M) 2501-1-M, stream 1-1 data symbol (M+1) 2501-1 M+1, and stream1-1 data symbol (M+2) 2501-1-M+2 as shown in the frame configuration inFIGS. 31 and 32, the base station may transmit another symbol groupusing a transmission beam different from “transmission beams fortransmitting stream 1-1 data symbol (M) 2501-1-M, stream 1-1 data symbol(M+1) 2501-1 M+1, and stream 1-1 data symbol (M+2) 2501-1-M+2.

Note that the same also applies to the case where the horizontal axisindicates frequency in FIGS. 31 and 32, and in time periods in which thebase station transmits stream 1-1 data symbol (M) 2501-1-M, stream 1-1data symbol (M+1) 2501-1 M+1, and stream 1-1 data symbol (M+2)2501-1-M+2, the base station may transmit another symbol group using atransmission beam different from “transmission beams for transmittingstream 1-1 data symbol (M) 2501-1-M, stream 1-1 data symbol (M+1) 2501-1M+1, and stream 1-1 data symbol (M+2) 2501-1-M+2.

In time periods in which the base station transmits stream 1-2 datasymbol (1) 3101-1, stream 1-2 data symbol (2) 3101-2, and stream 1-2data symbol (3) 3101-3 as shown in the frame configuration in FIGS. 31and 32, the base station may transmit another symbol group using atransmission beam different from “transmission beams for transmittingstream 1-2 data symbol (1) 3101-1, stream 1-2 data symbol (2) 3101-2,and stream 1-2 data symbol (3) 3101-3.

Note that in FIGS. 31 and 32, the same also applies to the case wherethe horizontal axis indicates frequency in FIGS. 31 and 32, and in timeperiods in which the base station transmits stream 1-2 data symbol (1)3101-1, stream 1-2 data symbol (2) 3101-2, and stream 1-2 data symbol(3) 3101-3, the base station may transmit another symbol group using atransmission beam different from transmission beams for transmitting“stream 1-2 data symbol (1) 3101-1, stream 1-2 data symbol (2) 3101-2,and stream 1-2 data symbol (3) 3101-3”.

In time periods in which the base station transmits stream 1-1 datasymbol (M) 2501-1-M, stream 1-1 data symbol (M+1) 2501-M+1, and stream1-1 data symbol (M+2) 2501-M+2 as shown in the frame configuration inFIG. 35, the base station may transmit another symbol group using atransmission beam different from “transmission beams for transmitting“stream 1-1 data symbol (M) 2501-1-M, stream 1-1 data symbol (M+1)2501-M+1, and stream 1-1 data symbol (M+2) 2501-M+2”.

Note that the same also applies to the case where the horizontal axisindicates frequency, and in time periods in which the base stationtransmits stream 1-1 data symbol (M) 2501-1-M, stream 1-1 data symbol(M+1) 2501-M+1, and stream 1-1 data symbol (M+2) 2501-M+2, the basestation may transmit another symbol group using a transmission beamdifferent from “transmission beams for transmitting stream 1-1 datasymbol (M) 2501-1-M, stream 1-1 data symbol (M+1) 2501-M+1, and stream1-1 data symbol (M+2) 2501-M+2”.

In time periods in which the base station transmits stream 1-2 datasymbol (N) 3101-N, stream 1-2 data symbol (N+1) 3101-N+1, and stream 1-2data symbol (N+2) 3101-N+2 as shown in the frame configuration in FIG.35, the base station may transmit another symbol group using atransmission beam different from “transmission beams for transmittingstream 1-2 data symbol (N) 3101_N, stream 1-2 data symbol (N+1)3101_N+1, and stream 1-2 data symbol (N+2) 3101_N+2”.

Note that the same also applies to the case where the horizontal axisindicates frequency in FIG. 35, and in time periods in which the basestation transmits stream 1-2 data symbol (N) 3101-N, stream 1-2 datasymbol (N+1) 3101-N+1, and stream 1-2 data symbol (N+2) 3101-N+2, thebase station may transmit another symbol group using a transmission beamdifferent from “transmission beams for transmitting stream 1-2 datasymbol (N) 3101-N, stream 1-2 data symbol (N+1) 3101-N+1, and stream 1-2data symbol (N+2) 3101-N+2”.

In time periods in which the base station transmits stream 2-1 datasymbol (1) 3501-1, stream 2-1 data symbol (2) 3501-2, and stream 2-1data symbol (3) 3501-3 as shown in the frame configuration in FIG. 35,the base station may transmit another symbol group using a transmissionbeam different from “transmission beams for transmitting stream 2-1 datasymbol (1) 3501-1, stream 2-1 data symbol (2) 3501-2, and stream 2-1data symbol (3) 3501-3”.

Note that the same also applies to the case where the horizontal axisindicates frequency in FIG. 35, and in time periods in which the basestation transmits stream 2-1 data symbol (1) 3501-1, stream 2-1 datasymbol (2) 3501-2, and stream 2-1 data symbol (3) 3501-3, the basestation may transmit another symbol group using a transmission beamdifferent from “transmission beams for transmitting stream 2-1 datasymbol (1) 3501-1, stream 2-1 data symbol (2) 3501-2, and stream 2-1data symbol (3) 3501-3”.

In the above, the “other symbol group” may be a symbol group whichincludes a data symbol addressed to a certain terminal, or may be asymbol group which includes a control information symbol or a symbolgroup which includes another data symbol for multicasting, as describedin other portions of the specification.

At this time, the base station in FIG. 1 may generate a transmissionbeam for the above “other symbol group” through signal processing bysignal processor 102, or may generate a transmission beam for the above“other symbol group” by selecting antennas from antenna unit 106-1 toantenna unit 106-M.

The base station in FIG. 3 may generate a transmission beam for theabove “other symbol group” through “signal processing by signalprocessor 102 and signal processing by weighting synthesizer 301” or“signal processing by signal processor 102 or signal processing byweighting synthesizer 301”.

Then, unicast transmitting sections 2503-1 and 2503-2 as illustrated inFIGS. 25, 31, and 32 may not be set.

Supplementary Note 5

A description with regard to FIGS. 31 and 32 includes the statement asfollows.

-   -   “Stream 1-1 data symbol (M) (for multicasting)” 2501-1-M,        “stream 1-1 data symbol (M+1) (for multicasting)” 2501-1-M+1,        “stream 1-1 data symbol (M+2) (for multicasting)” 2501-1-M+2,        “stream 1-2 data symbol (1) (for multicasting)” 3101-1, “stream        1-2 data symbol (2) (for multicasting)” 3101-2, and “stream 1-2        data symbol (3) (for multicasting)” 3101-3 are all data symbols        for transmitting “stream 1”.    -   A terminal can obtain “data of stream 1” by obtaining “data        symbols for stream 1-1”. Furthermore, a terminal can obtain        “data of stream 1” by obtaining “data symbols for stream 1-2”.

A description with regard to FIG. 35 includes the following statement.

-   -   “Stream 1-1 data symbol (M) (for multicasting)” 2501-1-M,        “stream 1-1 data symbol (M+1) (for multicasting)” 2501-1-M+1,        “stream 1-1 data symbol (M+2) (for multicasting)” 2501-1-M+2,        “stream 1-2 data symbol (N) (for multicasting)” 3101-N, “stream        1-2 data symbol (N+1) (for multicasting)” 3101-N+1, and “stream        1-2 data symbol (N+2) (for multicasting)” 3101-N+2 are all data        symbols to transmit “stream 1”.    -   A terminal can obtain “data of stream 1” by obtaining “data        symbols for stream 1-1”. Furthermore, a terminal can obtain        “data of stream 1” by obtaining “data symbols for stream 1-2”.

The following gives a supplementary description with regard to theabove. For example, in FIG. 35, the above can be achieved using <method1-1>, <method 1-2>, <method 2-1>, or <method 2-2> as below.

<Method 1-1>

-   -   Stream 1-1 data symbol (M) 2501-1-M and stream 1-2 data        symbol (N) 3101-N include the same data.

Then, stream 1-1 data symbol (M+1) 2501-1-M+1 and stream 1-2 data symbol(N+1) 3101-N+1 include the same data.

Stream 1-1 data symbol (M+2) 2501-1-M+2 and stream 1-2 data symbol (N+2)3101-N+2 include the same data.

<Method 1-2>

-   -   Stream 1-2 data symbol (L) 3101-L which includes the same data        as the data included in stream 1-1 data symbol (K) 2501-1-K is        present. Note that K and L are integers.

<Method 2-1>

-   -   Stream 1-1 data symbol (M) 2501-1-M and stream 1-2 data        symbol (N) 3101-N include the same data in part.

Then, stream 1-1 data symbol (M+1) 2501-1-M+1 and stream 1-2 data symbol(N+1) 3101-N+1 include the same data in part.

Stream 1-1 data symbol (M+2) 2501-1-M+2 and stream 1-2 data symbol (N+2)3101-N+2 include the same data in part.

<Method 2-2>

-   -   Stream 1-2 data symbol (L) 3101-L which includes a part of data        included in stream 1-1 data symbol (K) 2501-1-K is present. Note        that K and L are integers.

Specifically, a first base station or a first transmission systemgenerates a first packet group which includes data of a first stream,and a second packet group which includes data of the first stream,transmits a packet included in the first packet group in a first periodusing a first transmission beam, and transmits a packet included in thesecond packet group in a second period using a second transmission beamdifferent from the first transmission beam. The first period and thesecond period do not overlap.

Here, the second packet group may include a second packet which includesdata same as data included in a first packet included in the firstpacket group. As a configuration different from the above, the secondpacket group may include a third packet which includes data same as apart of the data included in the first packet included in the firstpacket group.

The first transmission beam and the second transmission beam may betransmission beams transmitted using the same antenna unit and havingdifferent directivities, or may be transmission beams transmitted usingdifferent antenna units.

In addition to the configuration of the first base station or the firsttransmission system, a second base station or a second transmissionsystem further generates a third packet group which includes data of thefirst stream, and transmits a packet included in the third packet groupin a third period using a third transmission beam different from thefirst transmission beam and the second transmission beam. The thirdperiod does not overlap the first period and the second period.

Here, the second base station or the second transmission system mayrepeatedly set the first period, the second period, and the third periodin a predetermined order.

Further, in addition to the configuration of the first base station orthe first transmission system, the third base station or the thirdtransmission system further generates a third packet group whichincludes data of the first stream, and transmits a packet included inthe third packet group in the third period using the third transmissionbeam different from the first transmission beam and the secondtransmission beam. At least a portion of the third period overlaps thefirst period.

Here, the third base station or the third transmission system mayrepeatedly set the first period, the second period, and the thirdperiod, the third periods repeatedly set may each at least partiallyoverlap the first period, or at least one of the third periodsrepeatedly set may not overlap the first period(s).

Further, in addition to the configuration of the first base station orthe first transmission system, a fourth base station or a fourthtransmission system further generates a fourth packet which includesdata of a second stream, and transmits the fourth packet in a fourthperiod using a fourth transmission beam different from the firsttransmission beam. At least a portion of the fourth period overlaps thefirst period.

Note that the first period and the second period do not overlap in theabove description, yet the first period and the second period maypartially overlap, the entire first period may overlap the secondperiod, or the entire first period may overlap the entire second period.

A fifth base station or a fifth transmission system may generate one ormore packet groups each of which includes data of the first stream,transmit the one or more packet groups using a different transmissionbeam for each packet group, and increase or decrease the number ofpacket groups to be generated, based on a signal transmitted from aterminal.

Note that the above describes “streams”, yet as described in otherportions of the specification, “stream 1-1 data symbol (M) 2501-1-M,stream 1-1 data symbol (M+1) 2501-1-M+1, stream 1-1 data symbol (M+2)2501-1-M+2, stream 1-2 data symbol (1) 3101-1, stream 1-2 data symbol(2) 3101-2, and stream 1-2 data symbol (3) 3101-3” in FIGS. 31 and 32,and “stream 1-1 data symbol (M) 2501-1-M, stream 1-1 data symbol (M+1)2501-1-M+1, stream 1-1 data symbol (M+2) 2501-1-M+2, stream 1-2 datasymbol (N) 3101-N, stream 1-2 data symbol (N+1) 3101-N+1, and stream 1-2data symbol (N+2) 3101-N+2” in FIGS. 31 and 32 may be symbols whichinclude data symbols addressed to a certain terminal, symbols whichinclude a control information symbol, or symbols which include a datasymbol for multicasting.

Supplementary Note 6

As a matter of course, the present disclosure may be carried out bycombining a plurality of the exemplary embodiments and other contentssuch as supplementary notes described herein.

As the configuration of the base station, the examples of theconfiguration are not limited to those in FIGS. 1 and 3, and as long asthe base station includes a plurality of transmission antennas andgenerates and transmits a plurality of transmission beams (transmissiondirectivity beams), the present disclosure can be carried out with sucha base station.

Moreover, the exemplary embodiments are mere examples. For example,while a “modulating method, an error correction coding method (an errorcorrection code, a code length, a coding rate and the like to be used),control information and the like” are exemplified, it is possible tocarry out the present disclosure with the same configuration even whenother types of “a modulating method, an error correction coding method(an error correction code, a code length, a coding rate and the like tobe used), control information and the like” are applied.

As for a modulating method, even when a modulating method other than themodulating methods described herein is used, it is possible to carry outthe exemplary embodiments and the other contents described herein. Forexample, APSK (such as 16APSK, 64APSK, 128APSK, 256APSK, 1024APSK, and4096APSK), PAM (such as 4PAM, 8PAM, 16PAM, 64PAM, 128PAM, 256PAM,1024PAM and 4096PAM), PSK (such as BPSK, QPSK, 8PSK, 16PSK, 64PSK,128PSK, 256PSK, 1024PSK and 4096PSK), and QAM (such as 4QAM, 8QAM,16QAM, 64QAM, 128QAM, 256QAM, 1024QAM and 4096QAM) may be applied, or ineach modulating method, uniform mapping or non-uniform mapping may beperformed. Moreover, a method for arranging signal points, such as 2signal points, 4 signal points, 8 signal points, 16 signal points, 64signal points, 128 signal points, 256 signal points, and 1024 signalpoints on an I-Q plane (a modulating method having signal points such as2 signal points, 4 signal points, 8 signal points, 16 signal points, 64signal points, 128 signal points, 256 signal points, and 1024 signalpoints) is not limited to a signal point arranging method of themodulating methods described herein.

Herein, it can be considered that communication/broadcast apparatuses,such as a broadcast station, a base station, an access point, aterminal, and a mobile phone, each include the transmitting device. Inthis case, it can be considered that communication apparatuses, such asa television, a radio, a terminal, a personal computer, a mobile phone,an access point, and a base station, each include the receiving device.Moreover, it can be also considered that each of the transmitting deviceand the receiving device according to the present disclosure is anapparatus having communication functions and has a form connectable viaany interface to devices for running applications such as a television,a radio, a personal computer, and a mobile phone. Moreover, in thepresent exemplary embodiment, symbols other than data symbols, forexample, pilot symbols (such as preambles, unique words, postambles, andreference symbols), and control information symbols may be arranged inframes in any way. Then, these symbols are named a pilot symbol and acontrol information symbol here, but may be named in any way, and afunction itself is important.

Moreover, the pilot symbol only needs to be a known symbol modulated byusing PSK modulation in a transmitting device and a receiving device.The receiving device performs frequency synchronization, timesynchronization, channel estimation of each modulated signal (estimationof CSI (Channel State Information)), signal detection, and the like byusing this symbol. Alternatively, the pilot symbol may allow thereceiving device to learn a symbol transmitted by the transmittingdevice by establishing synchronization.

Moreover, the control information symbol is a symbol for transmittinginformation that is used for realizing communication other thancommunication for data (data of an application, for instance) and thatis to be transmitted to a communicating party (for example, a modulatingmethod used for communication, an error correction coding method, acoding rate of the error correction coding method, setting informationin an upper layer, and the like).

Note that the present disclosure is not limited to the exemplaryembodiments, and can be carried out with various modifications. Forexample, the case where the present disclosure is performed as acommunication apparatus is described in the exemplary embodiments.However, the present disclosure is not limited to this case, and thiscommunication method can also be used as software.

Note that a program for executing the above-described communicationmethod may be stored in a ROM in advance, and a CPU may be caused tooperate this program.

Moreover, the program for executing the communication method may bestored in a computer-readable storage medium, the program stored in therecording medium may be recorded in a RAM of a computer, and thecomputer may be caused to operate according to this program.

Then, the configurations of the above-described exemplary embodiments,for instance, may be each realized as an LSI (Large Scale Integration)which is typically an integrated circuit having an input terminal and anoutput terminal. The configurations may be separately formed as onechip, or all or at least one of the configurations of the exemplaryembodiments may be formed as one chip. The LSI is described here, butthe integrated circuit may also be referred to as an IC (IntegratedCircuit), a system LSI, a super LSI, or an ultra LSI, depending on adegree of integration. Moreover, a circuit integration technique is notlimited to the LSI, and may be realized by a dedicated circuit or ageneral purpose processor. After manufacturing of the LSI, aprogrammable FPGA (Field Programmable Gate Array) or a reconfigurableprocessor which is reconfigurable in connection or settings of circuitcells inside the LSI may be used. Further, when development of asemiconductor technology or another derived technology provides acircuit integration technology which replaces the LSI, as a matter ofcourse, functional blocks may be integrated by using this technology.Application of biotechnology, for instance, is one such possibility.

Various frame configurations have been described herein. For example,the base station (AP) which includes the transmitting device in FIG. 1transmits a modulated signal having a frame configuration describedherein, using a multi-carrier method such as an OFDM method. At thistime, it is conceivable to apply a method in which when a terminal(user) communicating with the base station (AP) transmits a modulatedsignal, the modulated signal may be transmitted by the terminalaccording to a single carrier method (the base station (AP) cansimultaneously transmit data symbol groups to a plurality of terminalsusing the OFDM method, and the terminal can reduce power consumption byusing a single carrier method).

A time division duplex (TDD) method in which a terminal transmits amodulation signal, using a portion of a frequency band used for amodulated signal transmitted by the base station (AP) may be applied.

The configuration of antenna units 106-1, 106-2, . . . , and 106-M inFIG. 1 is not limited to the configurations described in theembodiments. For example, antenna units 106-1, 106-2, . . . , and 106-Mmay not each include a plurality of antennas, and may not receive aninput of signal 159.

The configuration of antenna units 401-1, 401-2, . . . , and 401-N inFIG. 4 is not limited to the configuration described in the embodiments.For example, antenna units 401-1, 401-2, . . . , and 401-N may not eachinclude a plurality of antennas, and may not receive an input of signal410.

Supplementary Description

The following gives supplementary description of the transmittingdevice, the receiving device, the transmitting method, and the receivingmethod according to the present disclosure.

A transmitting device according to an aspect of the present disclosureis a transmitting device which includes a plurality of transmissionantennas, the transmitting device including: a signal processor whichgenerates a first baseband signal by modulating data of a first stream,and a second baseband signal by modulating data of a second stream; anda transmitter which generates, from the first baseband signal, aplurality of first transmission signals having different directivities,generates, from the second baseband signal, a plurality of secondtransmission signals having different directivities, and transmits theplurality of first transmission signals and the plurality of secondtransmission signals at a same time.

Each transmission signal of the plurality of first transmission signalsand the plurality of second transmission signals may include a controlsignal for notifying which one of the data of the first stream and thedata of the second stream the transmission signal is for transmitting.

Each of the plurality of first transmission signals and the plurality ofsecond transmission signals may include a training signal for areceiving device to perform directivity control.

A receiving device according to an aspect of the present disclosure is areceiving device which includes a plurality of receiving antennas, thereceiving device including: a receiver which selects at least one firstsignal and at least one second signal from among a plurality of firstsignals for transmitting data of a first stream and a plurality ofsecond signals for transmitting data of a second stream, and performsdirectivity control for receiving the at least one first signal selectedand the at least one second signal selected, to receive the at least onefirst signal and the at least one second signal, the plurality of firstsignals and the plurality of second signals having differentdirectivities and being transmitted by a transmitting device at a sametime; and a signal processor which demodulates the at least one firstsignal received and the at least one second signal received, and outputsthe data of the first stream and the data of the second stream.

The receiver may select the at least one first signal and the at leastone second signal, based on a control signal included in each of aplurality of signals to be received, the control signal being fornotifying which one of the data of the first stream and the data of thesecond stream the signal is for transmitting.

The receiver may perform the directivity control using a training signalincluded in each of a plurality of signals to be received.

A transmitting method according to an aspect of the present disclosureis a transmitting method performed by a transmitting device whichincludes a plurality of transmission antennas, the transmitting methodincluding: signal generating processing of generating a first basebandsignal by modulating data of a first stream, and a second basebandsignal by modulating data of a second stream; and transmissionprocessing of generating, from the first baseband signal, a plurality offirst transmission signals having different directivities, generating,from the second baseband signal, a plurality of second transmissionsignals having different directivities, and transmitting the pluralityof first transmission signals and the plurality of second transmissionsignals at a same time.

A receiving method according to an aspect of the present disclosure is areceiving method performed by a receiving device which includes aplurality of receiving antennas, the receiving method including:receiving processing of selecting at least one first signal and at leastone second signal from among a plurality of first signals fortransmitting data of a first stream and a plurality of second signalsfor transmitting data of a second stream, and performing directivitycontrol for receiving the at least one first signal selected and the atleast one second signal selected, to receive the at least one firstsignal and the at least one second signal, the plurality of firstsignals and the plurality of second signals having differentdirectivities and being transmitted by a transmitting device at a sametime; and signal processing of demodulating the at least one firstsignal received and the at least one second signal received, andoutputting the data of the first stream and the data of the secondstream.

The present disclosure provides possibility of expanding a communicationrange in multicast/broadcast communication in which a plurality ofstreams are used, compared with the case where an antenna having aquasi-omni pattern is used.

INDUSTRIAL APPLICABILITY

The present disclosure is useful in communication in which a pluralityof antennas are used.

REFERENCE MARKS IN THE DRAWINGS

-   -   700 base station    -   701 antenna    -   702, 703 transmission beam    -   704 terminal    -   705,706 receiving directivity

1. A transmitting device which includes a plurality of transmissionantennas, the transmitting device comprising: a signal processor whichgenerates a first baseband signal by modulating data of a first stream,and a second baseband signal by modulating data of a second stream; anda transmitter which generates, from the first baseband signal, aplurality of first transmission signals having different directivities,generates, from the second baseband signal, a plurality of secondtransmission signals having different directivities, and transmits theplurality of first transmission signals and the plurality of secondtransmission signals at a same time.
 2. The transmitting deviceaccording to claim 1, wherein each transmission signal of the pluralityof first transmission signals and the plurality of second transmissionsignals includes a control signal for notifying which one of the data ofthe first stream and the data of the second stream the transmissionsignal is for transmitting.
 3. The transmitting device according toclaim 1, wherein each of the plurality of first transmission signals andthe plurality of second transmission signals includes a training signalfor a receiving device to perform directivity control.
 4. A receivingdevice which includes a plurality of receiving antennas, the receivingdevice comprising: a receiver which selects at least one first signaland at least one second signal from among a plurality of first signalsfor transmitting data of a first stream and a plurality of secondsignals for transmitting data of a second stream, and performsdirectivity control for receiving the at least one first signal selectedand the at least one second signal selected, to receive the at least onefirst signal and the at least one second signal, the plurality of firstsignals and the plurality of second signals having differentdirectivities and being transmitted by a transmitting device at a sametime; and a signal processor which demodulates the at least one firstsignal received and the at least one second signal received, and outputsthe data of the first stream and the data of the second stream.
 5. Thereceiving device according to claim 4, wherein the receiver selects theat least one first signal and the at least one second signal, based on acontrol signal included in each of a plurality of signals to bereceived, the control signal being for notifying which one of the dataof the first stream and the data of the second stream the signal is fortransmitting.
 6. The receiving device according to claim 4, wherein thereceiver performs the directivity control using a training signalincluded in each of a plurality of signals to be received.
 7. Atransmitting method performed by a transmitting device which includes aplurality of transmission antennas, the transmitting method comprising:signal generating processing of generating a first baseband signal bymodulating data of a first stream, and a second baseband signal bymodulating data of a second stream; and transmission processing ofgenerating, from the first baseband signal, a plurality of firsttransmission signals having different directivities, generating, fromthe second baseband signal, a plurality of second transmission signalshaving different directivities, and transmitting the plurality of firsttransmission signals and the plurality of second transmission signals ata same time.
 8. A receiving method performed by a receiving device whichincludes a plurality of receiving antennas, the receiving methodcomprising: receiving processing of selecting at least one first signaland at least one second signal from among a plurality of first signalsfor transmitting data of a first stream and a plurality of secondsignals for transmitting data of a second stream, and performingdirectivity control for receiving the at least one first signal selectedand the at least one second signal selected, to receive the at least onefirst signal and the at least one second signal, the plurality of firstsignals and the plurality of second signals having differentdirectivities and being transmitted by a transmitting device at a sametime; and signal processing of demodulating the at least one firstsignal received and the at least one second signal received, andoutputting the data of the first stream and the data of the secondstream.